372 Jouryial of Agricultural Research voi. vi, no. io 



Larvae of this species seem to be better equipped, more vigorous, and more 

 capable of defending themselves than the larvae of Micromelus subapterus 

 and Merisus destructor. E. allynii was reared from &gg to adult on larvae 

 of both the other species just mentioned as well as on the Hessian fly. 

 In one case, however, a newly hatched larva of E. allynii placed on a 

 full-grown lar\^a of M. subapterus in a glass cell was killed by the latter 

 almost immediately. A few instances were observed where larvae of E. 

 allynii killed ether individuals of the same species present in the same 

 Hessian-fly puparium. 



THE PUPA 



The lar\^a forms a naked pupa (PI. LI, fig. 3, 4) inside the puparium 

 of the host. The first step in the process is the excretion of all waste 

 matter from the body, leaving the larv^a pure white. The pupa is then 

 formed and the last larval skin cast off. The newly formed pupa is 

 nearly white, but turns dark within a few hours. The pupal stage 

 of 30 specimens reared in glass cells varied from 9 to 24 days. The 

 pupal period of those pupating in the summer averaged 13 days, while 

 the pupal periods of those reared late in the fall became as long as 24 

 days in some cases. The arrival of cold weather retards pupal develop- 

 ment, but whether or not the pupae are able to survive severe winter 

 temperatures has still to be determined. When the adult has completely 

 developed, the pupal skin is cast off inside the host puparium, and the 

 adult gnaws a round hole through the flaxseed near one end, penetrating 

 the leaf sheath covering the flaxseed, through which it emerges. 



THE ADULT 



After remaining quiet until dry, the adult becomes very active. Adults 

 do not seem to fly more than a few feet at a time, using their wings merely 

 to go from stem to stem. They do this so quickly and often that it is dif- 

 ficult to observe a single individual in the field very long. The females 

 run quickly up and down the wheat stems, vibrating their antennas 

 rapidly against the side of the stem until they come to a place where a 

 Hessian-fly puparium is located. Here they feel back and forth above 

 the flaxseed until they locate the exact spot which suits them for ovipo- 

 sition. Then, facing upward, the tip of the abdomen is bent down until 

 it touches the stem and raised away again, leaving the ovipositor pressed 

 vertically against the stem supported from its articulation with the mid- 

 dle ventral portion of the abdomen. The leaf sheath and puparium are 

 pierced by what under the microscope appears to be a sort of drilling 

 motion of the ovipositor, which seems to be rotated part way around and 

 back again. Oviposition takes several minutes. 



Males placed in the same cage with females usually attempt to mate 

 with them at once. Mr. W. R. McConnell has ascertained that this 

 species can reproduce parthenogenetically. The question of the sex 



