MORPHOLOGICAL ADAPTATION IN INSECTS — GRANDI 211 



How are the two phases of larvae formed? The larva of the first 

 phase in its free stage (jejune) is an oligopodous (hexapod), campo- 

 deiform, macrocephalous larva, with pigmented, sclerotized integu- 

 ments ; it resembles the so-called "triungulin" of the Meloidae (other 

 Coleoptera, which undergo hypermetamorphosis, also parasites of Hy- 

 menoptera Aculeata or of the egg clusters of Orthoptera Caelifera), 

 Its large head is prognathous and partly disintegrated; with rather 

 long antennae, five ocelli on each side; the mouth parts are fitted 

 for biting with large mandibles; legs with lanceolate, membranous 

 pretarsi ; there are nine pairs of stigmata. During its endophagous 

 stage (replete) it does not exhibit important modifications of any kind, 

 but has swollen until it looks like a little sausage. 



The larva of the second phase, enormously different from that of 

 the first phase, is a pseudopolypod, pseudoeruciform, microcephalous, 

 anophtalmous larva with membranous, depigmented integument ; its 

 thoracic limbs are transformed into rough, digitate processes; in the 

 abdomen there are 8 pairs of pseudopodia; thoracic and abdominal 

 segments armed with about 60 large subconical laterodorsal pro- 

 tuberances, which give it a monstrous look. The head capsule is small, 

 slightly sclerotized and subhypognathous ; the antennae are cupulate ; 

 there are no ocelli ; the mouth parts are peculiarly made, fitted for tear- 

 ing and sucking, the upper and lower lips (partim) form a sort of 

 membranous beak and the mandibles move obliquely without crossing, 

 with the tips turned out ; stigmata, shaped like a truncate cone, are 

 supported by short prominences. 



A life cycle like that of Macrosiagon and other Rhipiphoridae with 

 a protelic parasitism performed at the expense of such powerful, in- 

 dustrious Hymenoptera had of course the possibility of developing 

 in a simpler way, with fewer difficulties and hazards. This is shown 

 by the Cleridae (Coleoptera) belonging to the genus Trichodcs Herbst, 

 also parasites of Hymenoptera Aculeata ; they lay eggs near the nests 

 of the victim where the considerably modified larva reaches the host 

 pedotrophic cell by its own efforts and manages by itself to achieve 

 its objective. Therefore, as regards Rhipiphoridae, it is not possible to 

 speak of behavior related to necessity. We can only admit that the 

 life cycle of a coleopteran such as that of Macrosiagon (and allies), 

 beginning with the female habit of laying eggs far from the host nest, 

 required an agile, flexible, sheltered larva, whose mandibles had a 

 powerful hold and whose pretarsi were fit for helping these gnathites 

 to keep this hold, resisting adversities on all sides, supported in the 

 attainment of its purpose by a considerable fecundity of the female, 



