28 



DEPAETMENT BULLETIN 779. 

 NATURAL ENEMIES. 



PARASITES. 



During the course of the investigations in New Mexico one procto- 

 trypid parasite, Telenomm ashmeadi Morrill, was reared from the 

 eggs of Chlorochroa sayi, and two tachinid parasites, Gymnosoma 

 fuliginosa Desv. and {Ocyptera) Ocypterodes euchenor Walk, were 

 reared from the adults of the species. 



PARASITES OF THE EGG. 



Fig. 11. — Telenomus ashmeadi, an egg parasite of the grain 

 bug. Greatly enlarged. (Morrill.) 



The egg parasite Telenomus ashmeadi (fig. 11) constitutes one of 

 the most effective natural agents in the control of Chlorochroa sayi 



and is very widely 

 distributed through- 

 out the area infested 

 by the pest. During 

 the latter part of 

 July and the early 

 part of August, in 

 1915, adult parasites 

 emerged from about 

 60 per cent of the 

 eggs collected in 

 badly infested fields. 

 In many Qgg clusters 

 a parasite emerged 

 from each and every 

 egg. In all instances under observation it has been noted that 

 nymphs rarely hatch from an egg cluster when any of the individual 

 eggs produce parasites. Upon dissection these unhatched eggs gen- 

 erally are found to contain dead parasites or to be nearly devoid of 

 contents, apparently the result of parasitism. It is evident from 

 the foregoing that the percentage of eggs from which adult parasites 

 emerge does not necessarily indicate the full total of parasitism in 

 the field. | 



On July 27, 1916, a dozen reared parasites were confined in a glass 

 vial with a freshly deposited egg cluster of C. sayi. Within two 

 minutes the females began ovipositing. During this process the 

 female stands on the two posterior pairs of legs with the body nearly 

 vertical and inserts her short ovipositor into the egg, meanwhile 

 bending the head and antennae forward. They prefer to oviposit in 

 the top of the egg or in the side of the egg near its top. On August 

 13 the adult parasites began emerging from this egg cluster, a total 

 of IT days being required to complete the life cycle of the parasite 



