PARASITIC ROUNDWORMS 



539 



8 (i) Anterior region very slightly or not at all attenuated. Tip white, usually 



followed by a distinct dark ring 9 



Caudal end lobed; in female if not lobed then of uniform caliber with body or slightly en- 

 larged, but not set ofiE by a distinct constriction. 



9 (lo) Anterior region slightly attenuated, tip obliquely truncate; dark 



ring very broad Paragordius Camerano 1897. 



Caudal end trilobed in female and only bilobed in male. All males of Gordius also have the 

 caudal end bilobed. 



Montgomery rightly emphasized the absence of cloacal musculature in the male and the 

 exceedingly long cloaca in the female as most significant generic features to which the caudal 

 lobes were subordinate in value. For mere diagnostic purposes the latter are convenient. 



Only species in North America. . . Paragordius varius (^Leidy) 1851. 



Males more slender and considerably longer than females; up to 350 mm. long, 0.9 mm. 

 wide; female up to 290 mm. long, 2 mm. wide. 



The long trilobed tail of the female, the long cylindrical caudal lobes in the male, the obliquely 

 truncated head, and the usually very dark-colored ring around the head make its identification 

 easy. 



Montgomery found the larva only in Achaeta abbremala (Gryllus assimilis). Found by 

 Minnie E. Watson in the same host at Urbana, Illinois, and by H. G. May in the same host 

 and also in Nemobius fasciatus at Douglas Lake, Michigan. 



From New England to New York, Virginia (and southward? ; it is reported from Guatemala) ; 

 also Kansas and California. I have specimens from Lake Erie, Lake St. Clair, Lake 

 Michigan, and Nebraska. 



Fig. 8j6. Paragordiusvarius. o, lateral aspect of head. X 25. (Original.) 6. ventral view of tail. 

 X 25. (Original.) c, dorsal view of tail (female) . X 25. (After Stiles.) li, surface view of cuticula in 

 male and e, in female. Highly magnified. (After Montgomery.) 



10 (9) Anterior region not attenuated, tip usually rounded. 



GocfiiM.r Linnaeus 1758 . ii 

 Caudal end bilobed in male; simple, not enlarged in female. 



II (22) Caudal end bilobed, spirally inrolled. (Males of Gordius) 



12 



12 (13) Arcuate cuticular ridge anterior and lateral to cloacal pore. 



Gordius alascensis Montgomery 1907. 



Female not known; male 120 mm_. long, slen- 

 der, cylindrical. Head rounded. Caudal lobes 

 without hairs or spicules. Areoles irregular, in- 

 terconnected. Color dark brown with darker 

 neck ring. 



Fig. 837. Gordius alascensis. Cuticular areoles, 

 lateral and ventral views of tail. Magnified. (After 

 Montgomery.) 



