Other Nematodes developing in Arthropods 185 



Gigantorhynchus hirudinaceus {= Echinorhynchus gigas) is a com- 

 mon parasite of the pig and has been reported as occurring in man. 

 The adult female is 20-35 cm. long and 4-9 mm. in diameter. 

 It lacks an alimentary canal and is provided with a strongly spined 

 protractile rostrtmi, by means of which it attaches to the intestinal 

 mucosa of its host. 



The eggs are scattered with the feces of the host and are taken 

 up by certain beetle larv^. In Europe the usual intermediate hosts 

 are the larvae of the cockchafer, Melolontha vulgaris, or of the flower 

 beetle, Cetonia aurata. Stiles has shown that in the United States 

 the intermediate host is the larva of the June bug, Lachnosterna 

 (fig. 124). It is probable that several of the native species serve in 

 this capacity. 



A number of other nematode parasites of birds and mammals 

 have been reported as developing in arthropods but here, as in the 

 case of the cestodes, experimental proof is scant. The cases above 

 cited are the better established and will serve as illustrations. 



