62 



lirst three pairs are not of the chewing- type represented b^ 

 the last pair which is utilized by the larva for coarse work, 

 i. e. biting through the Gonocephalum integument and con- 

 suming by mouthfuls, the interior of the body. This morpho- 

 logical change in mandibles is common if not usual among car- 

 nivorous larvae of Hymenoptera. 



The full-fed Epyns larva is now very restless, it wriggles 

 about and works itself free of its shrivelled host, leaving it 

 with a gaping ventral hole, and after a brief period commences 

 to form a cocoon. It reaches about for grains of soil which it 

 attaches together with silk, thus forming a rough outer frame 

 in which it spins a very tough and firm cocoon (Fig. 7) that 

 tears cleanly like tinfoil, w^hich it somewhat resembles in being 

 smooth and silvery white within. It measures about 

 9 l)y 3 mm. and is a little broader and blunter anteriorly; 

 near this extremity the cocoon is partitioned off squarely 

 from the less firm terminal subconical portion, by a neat disc, 

 which, being rather thin along the edges, is there cut away 

 by the emerging wasp. The upper portion is then easily 

 ]uereed by the insect. The resting larva within is rather active 

 and bears the plainly visible compound eyes of the adult, as a 

 darker patch on the sides of second thoracic segment. There 

 is nothing remarkable about the whitish Epyiis pupa 

 (Fig. 8); it much resembles the adult in shape and size and 

 bears no or very few spines or protuberances, so characteristic 

 of many other wasps. The ovipositor is briefly exerted. The 

 cocoon period for August-September was about 23 days, 

 and with 2 1/2 days for the egg stage and 4 1/2 for the larval 

 feeding stage makes the life cycle in the laboratory about a 

 month. Perhaps the life cycle outdoors is more brief, a? the 

 (t once ph alum larva frequently, if not as a rule, lives buried 

 but a few inches in loose soil which during the day is kept 

 \-ory A\arm by the sun's rays. 



The adult wasp is an active flyer and superficially appears 

 much like a Tijjhia wasp; it may be found at flowers and at 



