254 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I4I 



Tetrastichus sp. I 



Taxonomy. — Burks (personal communication, 1956) stated that this 

 species (specimens of which are in the U.S. National Museum) is 

 very close to T. hagenowii. 



Natural hosts. — Periplancta aniericana, Union of South Africa 

 (parasites reared from oothecae collected in Durban, Natal, by the 

 City Health Department [Burks, p. c, 1956]). 



Periplaneta australasiae, Manila, Philippine Islands (Burks, p. c, 

 1956). 



Tetrastichus sp. II 



Synonymy. — Because of the war, Cros (1942) could not determine 

 this insect specifically. He designated it provisionally and with reserve 

 under the name Eulophus sp. However, Burks (p. c, 1956) stated 

 that the species is most certainly a Tetrastichus from the description 

 given ; but, it is apparently not T. hagenozvii because of its brilliant 

 steel-blue color. 



Natural host. — Blatta orientalis, Algeria (Cros, 1942) : Adult be- 

 havior. — Mating began as soon as wasps emerged from an ootheca. 

 Males mated repeatedly. Adults lived up to 5 days in summer and up 

 to 12 days in fall. There were up to four generations per year in the 

 laboratory, Oviposition. — Wasps oviposited into oothecae 6, 22, 40, 

 and 43 days old, and the parasites developed successfully. More than 

 one female oviposited into the same ootheca. Oviposition was of long 

 duration. Development. — From tgg to eclosion took an average of 34 

 days in summer (range: 30-38 days, 5 oothecae), and an average of 

 6y days in fall (range: 58-73 days, 3 oothecae). An average of 55 

 parasites developed per ootheca (range 21-105, 5 oothecae) ; over 130 

 wasps emerged from a sixth ootheca. Sex ratio. — 10-20 55 : i c^. 



HOST SELECTION BY EGG PARASITES 



The nature of the oviposition stimulus (i) for the wasp parasites of 

 cockroach eggs is unknown. Edmunds (1954) noted that Prosevania 

 punctata showed more interest in oothecae that had been cemented to 

 the substrate than in clean oothecae that had simply been dropped. 

 Cros (1942) experimented with two females of P. punctata to see if 

 the wasps could find oothecae that had been buried in sand by the 

 oriental cockroach. After prospecting the sand with their antennae, 

 the wasps dug deep excavations with their front legs but always mis- 

 took the location of the oothecae. Cros suggested that the wasps were 

 misled by the odor left in the jar by the cockroaches. It is quite 

 possible that odor helps the wasp find the host ootheca. 



