196 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I4I 



Ackert (1934) found about 50 percent of 222 P. americana infected 

 with H. diesingi. Sondak (1935) found about 36 percent of 412 B. 

 orientalis infected with either or both H. diesingi and Leidynema ap- 

 pendiculata. 



Two molts occur during development of the eggs ; the first takes 

 place outside the host resulting in a resting or infective stage. 

 After the tgg in the infective stage is eaten by the host, the second 

 molt occurs before the egg hatches. Completion of the second molt 

 and hatching perhaps are connected with ammonia present in the di- 

 gestive tract; the ammonia seems to arise from the bacteria present 

 in the gut. There appears to be a relationship between the intestinal 

 bacteria of the cockroach and development and hatching of nematode 

 eggs (Todd, 1944). 



At the time of oviposition the nematode eggs are in the very earliest 

 stages of cleavage. In 36 hours a motile, tadpole-like stage is reached 

 and in a few days the embryo becomes quiescent and nonmotile. This 

 nonmotile stage is infective whereas the motile embryonic stage is not. 

 Feeding experiments proved that transmission of the nematode is 

 direct. The worm reaches sexual maturity in 20 or 30 days after being 

 ingested by the cockroach (Dobrovolny, 1933). 



The bacterium Streptoniyces Jeidynematis Hofifman grows on the 

 cuticle of H. diesingi (Hoffman, 1953). The bacterium apparently is 

 only anchored to the nematode and probably obtains its food from the 

 intestinal contents of the cockroach. See notes under Leidynema ap- 

 pendiculata. 



Hammerschmidtiella neyrai Serrano Sanchez, 1945 



Synonymy. — Hammerschmidtiella neyrae Serrano Sanchez, 1947. 

 [According to M. B, Chitwood, personal communication, 1957, Ser- 

 rano Sanchez's emendation is apparently an error.] 



Natural host. — Blatta orientalis, Spain, Grenada (Serrano Sanchez, 

 1947) : Of 2,943 specimens examined, 1,143 were parasitized by 

 oxyurids and of these 45 percent contained H. neyrai. 



Leidynema appendiculata (Leidy, 1850) Chitwood, 1932 



Synonymy. — Oxyuris hlattae orientalis Hammerschmidt, 1847, of 

 Biitschli, 1871, and Oxyuris blattae-orientalis of Magalhaes, 1900) ; 

 Oxyuris hlattae Hammerschmidt, 1847, of Galeb, 1878 ; Aorurus 

 (Thelastoma) appendiculatus Leidy, 1850. [Chitwood, 1932.] Ser- 

 rano Sanchez (1947) has divided this species into three geographical 

 varieties as follows: L. appendiculata (Leidy, 1852) (Dobrovolny 



