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 rostrum, 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 larvae. 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. 
