RELATION OF INSECTS TO THE PARASITIC WORMS 77 



Setaria labiato-papillosa (Alessandrini, 1838) Railliet and Henry, 1911 



The adults of this nematode are common parasites in the peritoneal 

 cavity of cattle in various parts of the world including the United States. 

 The larvae enter the blood stream, and Noe (1903) identifies certain 

 larval nematodes found in Stomoxys calcitrans as belonging to this 

 species. That this fly actually serves as the intermediate host, however, 

 remains to be proved. 



The possibility is not excluded that Noe mistook Hahronema larvae 

 for the larvjB of .S". labiato-papillosa. 



Oncocerca 



About twelve species of this genius have been described. Onco- 

 cerca volvulus in the adult stage occurs in nodular tumors beneath the 

 skin of man in Africa. Oncocerca caecutiens is found in subcutaneous 

 nodules on the head among natives living at a certain altitude on the 

 west coast of Guatemala and is the cause of so-called "Coast erysipelas." 

 O. gibsoni causes worm nodules in the brisket and other locations in 

 cattle in Australia. Two species occur in cattle in the United States: 

 one undetermined species is found in relation with the ligaments of the 

 legs and neck, the other (0. lienalis) is found in the gastrosplenic liga- 

 ment. Oncocerca larvae have not been found in the blood stream but 

 may be recovered from the lymph spaces in the neighborhood of the adult 

 worms. The intermediate hosts of these nematodes are unknown but biting 

 insects have been suspected. The results of experiments have been nega- 

 tive. Brumpt (1903) has suggested the possibility that Glossina palpalis 

 acts as intermediate host of 0. volvulus. 



Robles (1919) suggests that two species of Simulium (close to S. 

 din^lli and S. samboni) may be involved as vectors of 0. caecutiens in 

 view of the fact that these flies are most numerous in the places where 

 the largest number of cases of Oncocerca occur. Furthermore these 

 species of flies are absent in lower altitudes corresponding with the absence 

 of Oncocerca. 



3. Other Nematodes 



Diff'erent investigators have recorded the occurrence of larval nema- 

 todes of unknown species in various insects. Usually these have been 

 very poorly described and it is questionable in many cases whether 

 if found again they could be recognized as the same forms. Some of 

 them may be the larval forms of nematodes whose adults are already 

 known as parasites of higher animals. Among such larvae of uncertain 

 identity may be mentioned Filaria geotrupis in the abdominal cavity 



