252 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I4I 



In Hawaii, Severin and Severin (191 5) caught 571 T. hagenozvii in 

 10 kerosene traps that were set up to sample populations of Mediter- 

 ranean fruitfly. Apparently the parasite is attracted by the odor of 

 kerosene. 



Oviposition. — The female wasp explores the surface of the ootheca 

 with vibrating antennae (Edmunds, 1955). She bends her abdomen 

 ventrad and repeatedly touches the surface of the ootheca with her 

 valvae ; when she finds an acceptable oviposition site, the wasp un- 

 sheathes her ovipositor and bores through the wall of the ootheca 

 (Roth and Willis, 1954b). The wasp deposited her eggs in 2-5 

 minutes (Edmunds, 1955). Wasps oviposited (pi. 34, C) into young 

 or old eggs of P. americana (Roth and Willis, 1954b). A single wasp 

 parasitized more than one ootheca and more than one wasp oviposited 

 into the same ootheca (Roth and Willis, 1954b; Edmunds, 1955). 

 We found freshly laid wasp eggs in 34 empty but previously para- 

 sitized oothecae from which the wasps had emerged (Roth and Willis, 

 1954b). 



Development. — In Periplaneta americana: Development is com- 

 pleted in an average of 2)^ days (range 29-58 days) (Maki, 1937) ; 

 29-40 days (Lever, 1943) ; average of 23.6 days (range 22-26 days) at 

 62°-85° F. (Usman, 1949) ; about 3 months at 6o°-65° F. (Cameron, 

 1955) ; 31-60 days at 70° -80° F. (Edmunds, 1955). We found that 

 the wasps completed development in 23-56 days at about 85° F., but 

 the period depended on the number of wasps in the ootheca ; the 

 larger the number of wasps (up to an average of about 70 wasps per 

 ootheca), the shorter the time required to complete development. 

 Wasps in oothecae containing 70 or more parasites developed in an 

 average of about 32 days (Roth and Willis, 1954b). Wasp larvae eat 

 the contents of the cockroach egg in which they start development, 

 then rupture the chorion and attack adjoining eggs (Cameron, 1955; 

 Edmunds, 1955). All eggs are consumed when the parasite density is 

 high, but if too few larvae develop per ootheca, some cockroach eggs 

 survive and the embryos complete development (Roth and Willis, 

 1954b). However, a certain number of cockroach nymphs must 

 complete development to enable the survivors to force open the crista 

 and emerge from the ootheca ; fewer than this number of surviving 

 nymphs will be trapped and killed as effectively as if they had been 

 eaten by the parasite. The adult parasites emerge from one to three 

 holes cut through the wall of the ootheca (Usman, 1949; Roth and 

 Willis, 1954b). 



Number of offspring per female. — In Blatta orientalis: In the 

 laboratory, 5 oothecae were left with each of 25 female wasps for their 



