igO SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I4I 



Paraclevelandia brevis Kidder 



Natural hosts. — Panesthia angustipennis, Philippine Islands, and 

 Panesthia spadica, Japan (Kidder, 1937) : Present in 100 percent of 

 P. angustipennis and in nearly all P. spadica. 



Paraclevelandia simplex Kidder 



Natural hosts. — Panesthia angustipennis, Philippine Islands 

 (Kidder, 1937, 1938) : Incidence of infection about 50 percent. 

 Panesthia spadica, Japan (Kidder, 1937). 



Unidentified ciliate 



Natural host. — Pycnoscelus surinamensis, Hawaii (Schwabe, 

 1950) : A large ciliate was found in the digestive tract and malpighian 

 tubules. 



NEGATIVE FINDINGS 



In a recent experimental study Schmidtke (1955) failed to demon- 

 strate a host-parasite relationship between Periplaneta americana and 

 the haemosporidian Toxoplasma gondii Nicolle and Manceaux. This 

 protozoan is a blood parasite in a rodent in North Africa (Kudo, 

 1954). 



XI. HELMINTHS 



Intestinal nematodes of the family Thelastomatidae have no ap- 

 parent pathological efifect on their cockroach hosts. Caleb (1878) has 

 shown experimentally that oxyurids eat the same food as the host in- 

 sect and that if one starves them, by withholding food from the host, 

 the oxyurids die and disappear. In other words, these worms are not 

 parasites, in the sense that we use the term in this paper, but commen- 

 sals. Dobrovolny and Ackert (1934) stated that "all observations 

 seemed to indicate that the health, fertility and activity of the heavily 

 infested cockroaches were comparable with those of the non-para- 

 sitised specimens." 



Very few papers have dealt with the ecology of the oxyurid para- 

 sites of cockroaches. According to Caleb (1878), usually one species 

 of nematode is found in a single cockroach, but sometimes two species 

 live together in the same host (e.g., in Blatta orientalis and Polyphaga 

 aegyptiaca) where they compete for food. Caleb claimed that Ham- 

 merschmidtiella diesingi would replace Leidynema appendiculata; he 

 observed that H. diesingi surpassed L. appendiculata in numbers and 

 the latter became uncommon in the intestines of the cockroaches. On 

 the other hand, Sobolev (1937) found that 48 percent of his oriental 



