LIFE AND WOEK OF FABRE — BOUVIER. 591 



established, was that it is the young larva of a blister beetle, but its 

 origin and destination were unknown. Fabre threw full light on this 

 problem to the great surprise of biologists. The Sitaris are developed 

 as parasites in the cells of Anthophora. They come forth in summer, 

 are paired and lay a great number of eggs which a month later yield 

 very active larva?, to which has been given the name of trinngulins. 

 These larvae pass the winter without food. In the spring they are 

 attached to the hairs of the male Anthophora, then to the females, 

 when the pairing is accomplished, and with these last enter into the 

 cell of their host. Once established in this home, it devours the egg 

 deposited by the bee on the cake of honey and pollen, moults, and 

 comes forth in the form of a scarcely moveable fat worm with very 

 short feet. Instead of being carniverous like the triungulin, this 

 second form of larva is nourished by the honey cake, prepared by 

 the bee, devours the cake entirely, moults, takes the form of an 

 almost footless pseudo-chrysalis, and passes the winter buried in its 

 exuvia. In the spring, moulting again, and in a new form of larva 

 the insect remains motionless, covered with two exuviae instead of 

 one. At the opening of summer this third form of larva transforms 

 into an entirely characteristic chrysalis and this one yields the adult 

 which throws off the two exuvial envelopes in order to leave the nest 

 of the Anthophora. These extraordinary phenomena were consid- 

 ered by Fabre as a hypermetamorphosis, that is, a complication of 

 normal development. It was not at all possible to characterize them 

 otherwise at the time they were brought to light. Since then it has 

 been possible to follow them among numerous blister beetles and to 

 establish their identity. The triungulin is evidently adapted to the 

 hunt for the host. As for the pseudo-chrysalis it is considered by 

 Edmond Perrier as a larva which is encysted at the time of high or 

 low temperature to await a more propitious season. The Meloe, 

 studied likewise by Fabre, is less abnormal than the Sitaris. 



After all, larval polymorphism is only one of numerous chapters 

 that Fabre has added to entomological history, and in doing this he 

 has helped to establish the extreme pliability of insects on their 

 coming from the egg, which serves to explain the singular predomi- 

 nance of these beings in the animal kingdom. The Leucospis gigas is 

 a chalcidoid Hymenoptera whose larvae devour those of the nesting 

 bees of the genus Chalicodoma. Several females of Leucospis are 

 likely to oviposit in the same cell of mortar which protects the future 

 victim and this can suffice only for the nourishment of a single para- 

 site. If all the Leucospis hatched, there would be famine. But poly- 

 morphism averts this danger. The first form of larva that issues 

 from the egg, is very alert and provided with long hairs that measure 

 the cell in every sense. The first hatched hastily destroys all the 



