BIOTIC ASSOCIATIONS OF COCKROACHES — ROTH & WILLIS 233 



the female. The female dies after completing oviposition (Barbier, 



1947)- 



Development. — The eggs hatch after 14 days, and the primary 

 (triungulin) larvae ascend the host's legs to its body; the larvae then 

 cut the intersegmental membrane between the metasternum and first 

 abdominal segment of the cockroach, in order to enter the host's ab- 

 domen (Barbier, 1947). Chobaut (1892) first suggested this method 

 of attack by the ripiphorid larva. As the parasites develop, the abdo- 

 men of the host becomes swollen. Developing larvae apparently eat 

 the host's fat body, leaving the vital organs until the last. Parasitized 

 female hosts were sterile and the eggs, when formed, never hatched. 

 Development of the ootheca was also inhibited. There were usually 

 two larval parasites per host, but three or four were found several 

 times (Barbier, 1947). Sundevall (1831) found only one larva per 

 cockroach except one host which, when crushed, yielded five. Stamm 

 (1936) found three hosts infested with five larvae each. In a little 

 over 100 cockroaches, Stamm found 10 that were parasitized. 



The day before the parasite leaves the host, the cockroach shows an 

 abrupt uneasiness and runs about, finally falling over on its back. The 

 parasite larva emerges from the host through an opening it makes in 

 the membrane between penultimate and last tergite. The host dies a 

 few hours after the larva has left. The larva seeks a sheltered area 

 and pupates within 48 hours. Adults emerge in 9 days (females) and 

 13 days (males) (Barbier, 1947). 



Distribution. — Adult males have been collected in light traps in 

 Hawaii (Van Zwaluenburg, 1946), and the first female was reported 

 by Weber (1948) ; the parasite is now established in the islands 

 around Pearl Harbor (Dr. F. X. Williams, personal communication, 

 1953). The U. S. National Museum has specimens of R. pectinicornis 

 from England, Guatemala, Hawaii, Panama, and from Florida and 

 Georgia in the U. S. (Dr. E. A. Chapin, personal communication, 

 1953). Kono {in Asano, 1937) reported two species in Japan. It is 

 noteworthy that all these records are from localities adjacent to oceans 

 and on ships ; none are from interiors of continents. The only biologi- 

 cal data were obtained from parasites found on board ships. Sundevall 

 (1831) believed that the parasites boarded his ship with their hosts 

 during loading in Calcutta, since before that not any were seen on 

 board. Barbier (1947) suggested that the parasite must be spread 

 very easily in ports between neighboring ships by parasitized cock- 

 roaches in baskets or sacks of provisions. 



Ripidius Scutellaria Heller 

 Natural hosts. — Blattidae, Philippine Islands (Schultze, 1925). 



