nomos LIV

Organic Evolution in terms of the Implicate and Explicate Orders.

Part L

Hymenoptera (wasps, bees, ants) (Sequel)

The evolutionary diversification in the Order Hymenoptera in terms of Strategies (Sequel).

Third vespine (crabroid) phase

As was shown above, the new, and comparatively more perfect work-order of wasps, having originated in complexificated circumstances during its establisment, still was encumbered by an essential insufficiency, namely the fact that to the place of the timely prepared nest had to be brought a prey taken in the random conditions of the hunt, and moreover being sufficiently large. As for this difficulty a way out was found. This could be accomplished thanks to the fact that the construction of the nest before supplying provisions, itself served as a base for further, and indeed for the core transformation of the providing-instinct. The fact is that precisely now the possibility was there to place a stock of provisions in the timely prepared cell, not in one definitive amount, as this took place until now, but in several, that is, supplying in measures. First, instead of the cell being provided with one rather big prey, two were brought in [one after the other] that were, however, of smaller size. See next two Figures.

Figure 1 : Two caterpillars of Geometridae [butterflies -- Carpets, Waves, Pugs, etc.] taken from a single cell of Ammophila apicalis. On one of them there is an egg of the wasp. Near the caterpillars lie lumbs of excrements, given off by them.
(After MALYSHEV, 1966)

Figure 2 : An egg of Ammophila apicalis Brulle adhered with the head-end on the side of the geometrid caterpillar. (After MALYSHEV, 1966)

In all this, the amount of labour of transportation of the prey is decreased, especially when preys are not at hand but must be taken from more or less distant places.

The work-order, in all this, now became a little different [from what it was before], and it may be expressed, using our symbols [For the meaning of the symbols, see HERE (previous document) ] thus :

B + A1 + C1 + D1 + A2 + C2 + E2

( preparing a nest, catching and paralyzing a prey, transporting the prey to and into the nest, oviposition on that prey, catching and paralyzing a second prey, transporting it to and into the [same] nest [and also the same cell], closure of the nest) (explanation follows)

In order to understand this consecutivity of acts, let us try to base things on the same principle as before (previous document). Let us suppose, consequently, that also in the present case cancellation of individual links from the ladder of serial actions took place followed by unification of the remaining links without transposition in time. Then we get [where "0" = zero] :

first series (B + A1 + C1 + D1 + 0) + second series (0 + A2 + C2 + 0 + E2) =
B + A1 + C1 + D1 + A2 + C2 + E2.

[ Originally, the individual series each belong to some one individual nest (or cell) built by the same individual wasp : A, B, C, etc. originally belong to the first nest. A1, B1, C1, etc. originally belong to the second nest. A2, B2, C2, etc. originally belong to the third nest. A3, B3, C3, etc. originally belong to the fourth nest. etc. The "first series", (B + A1 + C1 + D1 + 0), as here signified just above, thus is in fact a combination of the original first series and the original second series, while the "second series", (0 + A2 + C2 + 0 + E2), as here signified, belongs to the original third series.]

Let us now, to explain further, turn to the true activity. The digger wasp Ammophila urnaria Gress., according to observations by PECKHAM, 1898, usually places two (sometimes one) caterpillars into the cell, whereby it temporarily closes the nest two times -- first after having prepared the cell, and then after oviposition onto the first prey (on the second prey no egg is laid). Consequently, the complete work to provide one larva may in this case be written as :

(0 + B + 0 + 0 + E) + (A1 + B1 + C1 + D1 + E1) + (A2 + B2 + C2 + 0 + E2).

(Where E is the temporary closure of the nest (applying a cap), as is also E1, while E2 is the definitive closure of the nest. Further, B1 is, as B, a building (digging) activity, here, however, not the building of the nest (as is B), but the removal of the temporary cap of it. And the same goes for B2.)

The temporary closure (E and E1) of the cell and the removal of this temporary cap (B1 and B2) together make zero, and therefore, having subtracted E, E1, B1, B2, as elements that cancel each other, we will obtain the results of the work of Ammophila urnaria :

B + A1 + C1 + D1 + A2 + C2 + E2

which is what we sought for (see above ).
Apparently, the present method (way) of complexification of instincts (by way of cancellation followed by combination) also was taken further, proportionally to the growth of the number of preys in a cell in connection with the decrease of their size. At least there exists an indication, although insufficiently precise, that Ammophila yarrowii Gress. and A. polita Gress., bringing into a cell several (4-6) caterpillars, each time close the entrance of the nest. In the same way behave the small individuals of A. procera Dahlb., and partially also A. campestris Latr.
Temporary closure of the nest during providing is somtimes also done in other digger wasps. However this may be, the temporary closure and opening of the nest may, in certain circumstances, become superfluous and then totally disappear. Thus, A. holosericea L., which also provides for several (up to 5) preys, already does not temporarily close the nest. The cancellation of these superfluous acts, easing the work of the wasp, cooperated to further increase of the number of preys in a cell [per cell] with, of course, a corresponding decrease of their size. Moreover, the uniform repetition of a given act may create a certain inertia, which works in the same direction [i.e. contributes to the persistent cancellation of superfluous acts].
Now, this repetition, we have here, a repetition, that is, without substantial change of actions carried out at the previous moment, undoubtedly also was of great significance to the working-out of maternal instincts in wasps and bees. The most characteristic examples of such "mass-providing" of each cell with a number of similar [among each other] preys is encountered in the majority of solitary wasps (especially of the families Crabronidae, Oxybelidae, Trypoxylonidae, Mellinidae, Nyssonidae, Pemphredonidae (see next Figure), and also of the plaited-winged wasps (Eumenidae)).

Figure 3 : Nest of Psenulus fuscipennis Dahlb. Pz. The cells are filled with aphids.
1 - a just emerged larva of the wasp. 2 - separation wall. (After MALYSHEV, 1966)

Taking into account the indissoluble consecutivity -- in such a provision -- of two acts, namely the hunt (A) and the bringing-in of the prey (C) into the cell, the previous series may be given by :

B + A1C1 + D1 + (A2C2)n + E(n+2)

or, in a more general form :

B + AC + D + (AC)n + E

(indices as to what series the individual acts belong, now omitted)
where (AC)n signifies the hunting acts corresponding to the number of preys (n) to be prepared after oviposition (D). So the formula means : building of the nest, catching and bringing-in the first prey, oviposition onto this first prey, repeated catching and bringin-in of additional preys [into the same cell] (without oviposition), closure of the nest.

In solitary wasps, in an increased rate preparing for several preys in one single cell, sometimes also another complexification is observed. It consists of the fact that the egg is deposited, not onto the first prey that has been brought in, but onto one of the next preys or even onto the last one, which [latter] may be espressed as :

B + (AC)n + D + E

In this case, where we have to do with a high rate of provision, in these wasps not interrupted by another activity (temporary closure and opening of the cell, periods of awaiting), the act of oviposition looses its connection with the first-brought-in prey, and now comes only at the completion of the provision such that the closure of the cell follows directly upon oviposition. So do behave, for example, the American species of Sceliphron and Podium. For a Palaearctic representative of the genus Sceliphron, see next Figure.

Figure 4 : Sceliphron destillatorium. 15-30 mm. (Europe, Central-Asia, Iran). Family Sphecidae.
(After SEVERA, in Thieme's Insektengids voor West- en Midden-Europa, 1977)

Parallel to the increase of the number of preys to be prepared in a cell, the qualitative selection of the provision also changed. If we survey the preys of he wasps of the present group [these wasps] bringing into each cell several preys, then we are struck by the unusually wide qualitative content of the [collection of] preys, far surpassing all what is observed in the previous Phases of the evolution of wasps [That is, the range of possible preys (prey-types) is much larger than it is in the previous Phases, where specialization with respect to prey-type is much more the rule].
Of the original preys of the wasps in the present Phase we can mention caterpillars. Here they are rarely encountered, and look as if they are rudiments of ancient habits still preserved in Ammophila, that also earlier used caterpillars. Later were used, also as an exception, cockroaches, for a large part young ones, and living in natural conditions. For them chiefly hunt wasps of the genus Podium living in tropical America, and relatives of them, related to Sceliphron.
According to data of WILLIAMS, 1928, Podium flavipenne Latr. nests in hard soil, where it constructs a short burrow widened at its end. In order to ease the digging work, the wasp from time to time flies to the water and with it softens the soil, and the lumps of [thus] moistened soil that are dug out are disposed of nearby, forming a characteristic 'slag-heap'. When the burrow is finished, the wasp hunts for young and adult cockroaches Epilampra abdomen-nigrum (De Geer), living at the roots of bushy herbs. With the paralyzed prey the waps flies to the nest. In each cell it most often prepares two cockroaches, sometimes three, more rarely one or four and even five. The egg is deposited upon the cockroach that was brought in as the last one. This [oviposition] takes place in exclusive circumstances. Bringing in the prey, the wasp descends with it near the entrance to the nest, bends the tip of its abdomen under the cockroach and adheres an egg behind one of the prey's forelegs. Thus, oviposition takes place outside the nest and not inside the cell, as do all other wasps, a fact that demands special explanation. Another species, Podium (Trigonopsis) abdominale Kohl., molds cells of mud -- as does also our Sceliphron, which hunts for spiders -- but carries into these cells still cockroaches.
It is interesting that among the representatives of the family Larridae also are hunters for cockroaches. Thus, the European species Tachysphex lativalvis Thoms. hunts for woodland cockroaches -- Ectobius lividus F. and Ectobius lapponicus L. See next Figure.

Figure 5 : Egg of Tachysphex lativalvis Thoms. deposited transversely on the thorax of the cockroach Ectobius lividus. (After GRANDI, 1929, in MALYSHEV, 1966)

Other species (Tachysphex mantiraptor Fert., T. julliani Kohl.) hunt for young praying mantises (mantids), that is, for representatives of an insect Order (Mantoptera) close to that of the cockroaches (Order Blattoptera) [in IMMS' Texbook of General Entomology, 1977, the cockroaches and the mantids are placed in one and the same insect Order, the Dictyoptera]. In one cell are placed 3-16 paralyzed mantids, and the egg is deposited upon one of the last of them or upon the last mantid having brought into the cell. The long body of the mantid does not completely fit into the cell of Tachysphex and projects from it out into the nest channel. Such non-correspondence of the sizes of the cell and the prey tells us, apparently, that the building instinct here in its development lagged behind the selection of prey, and that this cell once contained another prey having a normal size such as cockroaches. For mantids also hunts Stizus ruficornis F. (Stizidae).
In the presently considered group of Larridae we already do not encounter hunters for true mole crickets (Gryllotalpidae). But it is remarkable that also here one American species, Tachytes mergus Fox., still hunts for the "pygmy-mole cricket" (Tridactylus apicalis Say.), which is a minute being, unusually dexterous, with an enormous ability to jump. But the wasp not only succeeds in seizing it at the moment of the jump but also in paralyzing it in the air. Half a dozen of these "minute mole crickets" are installed in one shallow burrow. Paralyzation of them is not total, or [it is] temporary, but they already do not use their fossorial forelegs for getting out of the cell.
As preys further serve here crickets, katydids, grasshoppers, locusts, cicadas. Later a number of new preys, also insects with an incomplete metamorphosis, were added, such as bugs (Hemiptera-Heteroptera) (Figure 6), aphids (Hemiptera-Homoptera), jumping plant lice (Hemiptera-Homoptera, Psylloidea), booklice and allies (Psocoptera), thrips (Thysanoptera) (Figure 7), mayflies (Ephemeroptera), and even spring-tails (Collembola) from the lower primarily wingless insects.

Figure 6 : Content of a cell of the wasp Dinetus pictus F.
Left : Five paralyzed bugs (Hemiptera) Reduviolus ferus L. with an egg of the wasp on one of them -- onto the middle one.
Right : The bugs, taken out of the cell. (After MALYSHEV, 1966)

Figure 7 : Nest of Spilomena troglodites Lind. made in a stalk. In the cells are provisions consisting of paralyzed thrips.
1 - egg of wasp. 2 - dividing wall. (After MALYSHEV, 1966)

As to earwigs (Dermaptera), stick- and leaf-insects (Phasmoptera [Phasmida]), termites (Isoptera), and some others,-- they have, apparently, not been encountered on the paths of evolution of solitary wasps, and therefore are also not encountered in them today as preys. On the other hand, spiders are taken as preys also in the present Phase, but are represented by smaller forms, and especially [by] cross spiders (Epeiridae).
It is certainly possible that precisely the delicacy of the prey is its chief attracting property to many wasps. In this respect interesting, for example, are the data concerning nesting of the diverse wasps of the genus Gorytes Latr. with the subgenera Gorytes s.str., Hoplisus Lep., Harpactes [must probably be Harpactus] Dahlb., Lestiphorus Lep.
Unfortunately, the observations in this respect are still insufficient. As far as is known, all of them hunt for cicadas (especially of the Cercopidae, and partly of the Membracidae), placing into the cell 5-60 individuals of them depending on the species of wasp, whereby one burrow may contain 6-9 cells. It is interesting that here the prey most often consists of "foam-beasts" (Aphrophora, Philaenus [Hemiptera-Homoptera, Aphrophoridae] ), but not adults, but their delicate nymphs, living inside foam, secreted by them on herbs, and sometimes on trees, and simply called "cuckoo's spit". See next Figure.

Figure 8 : "Cuckoo's spit" -- a foamy mass, formed on a stalk of an euphorbia by nymphs of the cicada Aphrophora sp. (After MALYSHEV, 1966)

In order to pull out such an, apparently, strange, not directly visible, prey from the foamy mass surrounding it, the wasp has to penetrate into the foam not only with its sting, but also with its legs.
As to the oviposition by the Gorytes's, the relevant statements are still very insufficient. ADLERZ, for instance, having observed the nesting behavior of Gorytes campestris Mull., did not find, in any cell, an egg, nor a larva, but only a prey -- the foam-beast (Homoptera-Aphrophoridae). Inadvertently, doubt may come up whether the egg might not be discerned because perhaps it has been deposited without sufficient adherence to the prey's body, such that it could easily fall off and get lost. Moreover, disappearance of eggs in wasp cells, that were provided [with prey] just a minute ago, is very often the consequence of their being destroyed by larvae of viviparous metopia flies (Metopiinae), whereby these larvae, after having destroyed the egg of the wasp, at the same place, conceal themselves inside the prey [So these metopia flies [Diptera-Cyclorrapha] are in fact inquilines of wasp cells]. Therefore the impression is created that the egg of the wasp has not been laid at all. According to observations of HARTMAN, the cell of another Gorytes, Hoplisoides sp., occurring in Texas (USA), contained 7 cicadas (Membracidae), and on one of them there was an egg of the wasp. " The egg, having a length of 2 mm, was adhered to the ventral side of the cicada near the lateral edge of the thorax and parallel to it, nearby the first and second pair of legs" (HARTMAN, 1905).

Similar things tell us FERTON,1901, and GRANDI,1926, about Gorytes. According to REINHARD, 1925, Hoplisus costalis Gress. adheres its egg to the thorax of a cicada (also of the Membracidae) only with one end, but which one [head or tail end] is not indicated.

On the 2nd of August, 1949, the author [Malyshev] succeeded in finding a nest of Harpactus [subgenus of Gorytes] tumidus in the Chopersky nature reserve. In the just provided [with prey] cell there were 11 cicadas present -- Jassidae -- of which 5 adults and 6 nymphs. The egg of the Gorytes was present on precisely that adult cicada that had been placed in the very depth of the cell, and brought in, we should think, as the first prey. See next Figure.

Figure 9 : Egg of the gorytes Harpactus tumidus Pz. on the cicada-jassid (Jassidae), taken from the cell of the wasp. (After MALYSHEV, 1966)

It had a length of 1.5 mm and rested along the ventral side of the cicada, beside its left legs. The egg's wider end was directed anteriorly, to the head of the cicada, and its narrower end was directed tailward. By reason of the fact that in other wasps (in Bembex'es (Sphecoidea) and Stizus'es (Stizidae)) the narrower end of the egg corresponds to the head-end of their larva, we can assume the same relationship holding also here (Harpactus) [That is, in the case of Harpactus the narrow end of the egg would also correspond to the head-end of the larva in that egg, and that, consequently, this head-end is directed toward the posterior end of the cicada].
Unfortunately, this could not be confirmed here [by Malyshev], because the egg of Harpactus tumidus had a very delicate shell. It was deformed the other day and perished. Nevertheless, it is interesting that the egg was hardly in real contact with the body of the prey, and with the lightest touch (when it was attempted to remove from it dust-particles having been sticked on it) became almost completely detached from its place.
This fact is an essential condition for the formation of the next Phase, presupposing [that is, having itself evolved from] the absence of a special instinct to adhere the egg to the body of the prey, or such [an instinct] that lets the egg only weakly to be attached with only its posterior end.

But most remarkable in the present Phase is the wasps hunting for adult insects with complete metamorphosis (Holometabola) -- flies (see next Figure), midges, beetles (next next Figure), butterflies, bees, wasps, ants, terebrants [= parasitic wasps], and others.

Figure 10 : Content of a cell of the wasp Crabro chrysostomus Lep.
A - Two fruit-flies Otites formosa Pz.
6 - One stratiomyid fly Eulalia hydroleon L.
B - One tachinid [fly, as larva endoparasitic] Dexiomorpha sp. with an egg of the wasp.
Right image - Fruitfly. The egg of the wasp is visible. It is adhered with its head-end toward the throat (of the prey).
(After MALYSHEV, 1966)

Figure 11 : Content of a cell of Cerceris quinquefasciatus consisting of 29 small leaf-eating beetles (Chrysomelidae) and weevils (Curculionidae). (After MALYSHEV, 1966)

The characteristic attachment ('devotion') of these or those wasps to one fairly determined [specific] prey, is striking. Here, specialization within the limits of the species usually goes together with a significant variability within the limits of the genus : Different species of one and the same genus of wasps not seldom select a prey very different from the preys of the other species of its genus, and typical to themselves. Here, however, not only individual species, but also whole genera, and even groups of related genera, often show an attachment to preys of one determined group (for instance, to orthoptera), and this, not in connection with mere local [and more or less the same] conditions [i.e. this attachment to preys belonging to one determined group, is not some local (and thus locally caused) phenomenon], but, the other way around, in [connection with] different conditions even in different continents [i.e. despite different conditions and even different continents, the mentiond phenomenon prevails]. Thus, the Tripoxylonidae, and Sceliphron's everywhere hunt for small spiders, and the Ammophila's [everywhere] for bald caterpillars.
Unfortunately, we cannot pause here at something more precise regarding the question of the biology of wasps. The author would like to clarify this question only from one point of view, namely from the evolution of the instinct of selecting the prey. Already in terebrants [parasitic wasps] we saw specialization in selecting the prey, where this specialization is for the greater part sufficiently or [even] in a fully determined way expressed. In spite of the enormous diversity prevalent in this respect, we see here also clear limits, allowing us to say that the terebrants, even in their broadest sense, chiefly parasitize on young stages of insects (egg, larva, pupa), and sometimes on spiders and their eggs.
The comparatively rare cases being observed among terebrants of oviposition onto adult insects also is in line with the history of their origin, expounded earlier. After all, the ancestors of the terebrants began oviposit onto the eggs or onto the larvae of adult individuals similar to them, and [evolutionarily] later also onto other insects in their young stages. Essentially, in this phase the terebrants remained up until now, if we do not count parasitism by a number of them on spiders and the special cases of imaginal parasitism [= parasitizing on adult insects], dealt with earlier.
It is therefore not surprising that the lower [true] wasps precisely hunt, on the one hand, for larvae of beetles, butterflies and hymenoptera [ as to the latter : chiefly, I assume, of saw-flies, and not others, if we have in mind solely nest-building wasps], and, on the other hand, for spiders, a fact that we also saw in the previous phases of vespine life. So it is very indicative that the nursing of offspring at the expense of adult insects with complete metamorphosis (flies, beetles, hymenoptera, butterflies) is precisely observed among higher digger wasps (of the Sphecoidea). Here, to one cell are always brought several such preys, and usually several such cells together make up one nest, a feature that is, as was explained, already all by itself pointing to the great hight [high level] of the development of the instinct of provisioning.
Now the basic question arises as in what way the wasps, in the previous phases of their evolution having brought in -- if we do not count spiders -- only insects with incomplete metamorphosis (Hemimetabola) or only larvae of higher insects (Holometabola), now began to select [adult] Diptera (horse flies [Tabanidae], flies [fruit flies, etc.], midges) and Hymenoptera (terebrants, wasps, bees, ants), that is, to select precisely those [adults of the] higher insects, the larvae and pupae of which they have never hunted-for in earlier times, neither do they so today [They hunt for larvae of butterflies (Lepidoptera) and possibly for larvae of saw-flies (Hymenoptera), but do not hunt for larvae of Hymenoptera or of Diptera, if we by "hunt for" only count catching a prey and bringing it to a nest, and not count inquilinism or parasitism] [So there seems to be no transition having taken place from hunting for the immature stages of (the mentioned) holometabolous insects to hunting for their corresponding adult forms]. If we assume that the instinct of selecting the prey in wasps evolved slowly, step by step, going from one form to the other, and the latter only deviating little from the former, then it is totally impossible to imagine how this graduality is compatible with those cases in which the preys belong to holometabolic insects. There is even no such hint of graduality as there might be (such a hint) (for instance, a hunt for pupae of beetles and butterflies), because we do not know of a single wasp which would select pupae. Moreover, when we try to build a natural bridge between insects and spiders, then this leads to such remote times at which neither wasps no spiders already existed undoubtedly. It is also not possible to carry through this connection [relating to the transition in prey selection from larvae of holometabola to their adult forms on the one hand, and from these larvae to spiders, on the other] following the principle of mimicry : for such an impossibility it is already enough to realize that there is nothing [morphologically or physiologically] in common between the larvae and adult holometabolous insects or spiders. Therefore we come to the conclusion that the evolutionary development of the instinct of qualitative selection of provisions [prey] in wasps did not correspond with that particular graduality and consecutivity by which the animals evolved that later have become these provisions.
On the other hand, when we do not see any great morphological similarity between the preys of different wasps, it is nevertheless not difficult to assume (in certain cases at least) an ecological similarity between preys, that is, some similarity in the way of life of these or those preys. We will meet with fine examples of this later on, but [we should realize that] also this path of qualitative selection of prey by wasps can hardly be seen as a broad one [a much trodden one] [That is, transition in prey selection from some given type of prey to another that in its way of live differs only slightly from the original prey (It can be found in the same places, and is accessible in the same way), is easy, but is not the only possible way for such a transition to take place].
We must not forget that in many cases, if not, the majority, terebrants and wasps (especially terebrants) are guided in their selection [of prey] not even by the mere visual image of the prey, although vision (especially in wasps) also here often has great significance. It is possible that terebrants and wasps chiefly make use of some unknown sense. Anyway, all this does not resolve the question, but only brings it to another plane. When the difference between the preys looks great to us, it may be insignificant to this unknown sense. But with all this, nothing is yet said about the method of obtaining that selected prey.
As soon as a transition had taken place from one prey to another that greatly differs [from our human point of view] from the original one [especially when this difference brings with it a great ecological difference], then, corresponding to that difference, also had to change the methods of finding these [new] preys, of the struggle, of paralyzation, of transporting, of dragging them into the nest, and even of oviposition.
So also here the change of a single link in the chain of the serial instinct inevitably must bring with it a corresponding [compatible] change in the others. The ability of self-regulation of the instinct, having come forward also in other above described cases, appeared, evidently, also this time.
The very transition from one prey to another differing more or less from the first one, could have been taken place in different ways. In some cases, the wasps (here we will have in mind only them) directly, albeit not completely, left their original prey and went over to a new one, generally as determined as was the first one. It is remarkable that such transitions are sometimes still observed today. Thus, according to observations of ADLERZ, Crabro (Lindenius) albilabris F. in some places selects only flies (Muscidae), a few miles more to the south, however, it carries flies and herb-bugs (Hemiptera-Capsidae), and still more south, it selects only these bugs. In the same way behave Crabro (Crossocerus) anxius Wesm and Coelocrabro cinxius Dahlb.
When [as the case might be], in these wasps, to one and the same cell is brought one and the other prey [two types of prey in one and the same cell], then the egg of the first species (Crabro anxius) is laid onto the bug, and in the second species [I take this to be Coelocrabro cinxius] onto the fly. Also Rhopalum elavipes L. hunts for booklice (Psocoptera-Psocidae) as well as for midges [Diptera] of the families Cecidomyidae and Mycetophilidae. Sphex flavipennis F., the "passionate hunter for crickets", in the form of an exception sometimes selects the "common grasshopper" (FABRE, 1906). When in such cases a cancellation of the hunt for one of the two sorts of prey takes place, then the wasp, evidently, will specialize on the second.

The notification (SMIRNOV, 1915) that Ammophila (Eremochares) dives Brullé selects grasshoppers (and not caterpillars or pseudo-caterpillars [larvae of saw-flies] ) is, apparently, incorrect. This also is the opinion of BERLAND, 1925.

The second possible evolutionary path along which was realized the change in prey selection consisted of the fact that one and the same wasp began to carry to its cell very different [from each other] preys. Thus it is known that Palarus flavipes F. simultaneously collects different genera of terebrants, waps, and bees (Ichneumon, Tiphia, Myzine, Mutilla, Scolia, Cerceris, Philanthus, Lyrops, Crocia, Sphecodes, Ammobates, Andrena, Apis). There are, however, no indications that later these wasps might specialize on some one of the preys taken initially.
As we will see later, this is still not the limit of possible selection of prey by the solitary wasps. We get the impression that the instinct of the insect, having reached a certain high level of development, enters, as it were, a special pliable condition [of it], easing further possibility of its evolution.

Summarizing what has been expounded, we see, on the one hand, together with the great effort needed to drag [it] over the ground, the very large but single [one and only] prey, being many times (15 times in Psammophila hirsuta Kby. and Ammophila sabulosa L., according to FABRE) heavier than the wasp having attacked it, and on the other hand [we see] whole tens of small forms [as prey] (aphids, small caterpillars, ants), which are carried to the cell by air with unsurpassible speed and ease. In this way the instinct has coped with the weight of the prey. As a result, the preparation of provisions, [evolutionarily] earlier being simple, consisting of one single act, now has become to consist of many acts [repeatedly catching and bringing in (small) prey]. In this state the provisioning indeed is found to be in all higher wasps and in all bees nesting independently.
In the present[ly under discussion] Phase of [hymenopterous] evolution, in addition to the paralyzation of the prey up to this or that measure, and also to the overpowering of it with its sting or jaws, from time to time maiming of the prey is observed. From its prey the wasp bites off parts of one or several legs, and sometimes also the antennae, which [operation] increases the manageability of the prey and eases the placing of it in the cell. In this way processes, for example, Notogonia pomiliformes Pz. crickets, Sphex maxillosus F. -- katydids, Sphex albisectus Lep. -- grasshoppers. Sometimes of the prey, on that side of it where the egg of the wasp (Crabro, Oxybelus) is laid, the wasp turns out the wing [of the prey], preventing, apparently, the prey from falling over, and with it the egg, onto the bottom of the cell.
Regarding the "chewing" of the prey [by the wasp] at the region of its head or thorax, also this operation is sometimes observed in the present Phase, and in certain cases this act acquired here a special significance. Thus, in the American species of Diodontus the chewing of the prey (aphid), apparently, totally replaced paralyzing it with the sting.

With all this we conclude our exposition of the Third Vespine (Crabroid) Phase of hymenopterous evolution.
In the next document we will deal with the Fourth Vespine (Bembecoid) Phase.

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