GORDIACEA 227 



Family 1. GORDIIDAE. 



With the characters of the order: 4 genera. 



Key to the genera of Gordiidae here described: 



tti Hinder end bilobed or trilobed. 

 6i Hinder end bilobed and rolled spirally. 



Ci Head end not obliquely truncated 1. Gordius (male) 



Cj Head end obliquely truncated 2. Paragordius (male) 



62 Hinder end trilobed 2. Paragordius (female) 



O2 Hinder end not forked. 



61 Hinder end rolled spirally 3. Chordodes (male) 



62 Hinder end not rolled spirally. 



Ci Hinder end not swollen 1. Gordius (female) 



Ca Hinder end swollen and knob-like 3. Chordodes (female) 



1. Gordius L. Hair worms with a forked and spirally rolled tail 

 and often a V-shaped ridge behind the anus in the male, and a straight, 

 unforked tail in the female: about 10 species. 



G. aquaticus L. {G. robustus Leidy) (Fig. 361). Length 28 to 89 

 cm.; thickness .5 to 1 mm.; color white or brown; ends blunt; V-shaped 

 postanal ridge in male: cosmopolitan. 



Fig. 361 Fig. 362 



Fig. 361 — Gordius aquaticus; hinder end of male (Montgomery). Fig. 362 — 

 Gordius lineatus; hinder end of male (Montgomery). Fig. 363 — Paragordius varius ; 

 hinder end of female (A) aud male (B) (Montgomery). 



G. lineatus Leidy (Fig. 362). No distinct V-shaped ridge behind 

 the anus, on each side of which in the male is a longitudinal line of 

 hairs; color yellowish-white; female with longitudinal rows of cuticular 

 areoles: eastern states. 



2. Paragordius* Camerano. Hair worms with a forked and spirally 

 rolled tail in the male, and a trilobed tail in the female: 1 species. 



P. varius (Leidy) (Fig. 363). Length 10 to 30 cm.; head of male 

 obliquely truncated; the commonest gordian: occasionally occurs in 

 human digestive tract; North America. 



3. Chordodes Mobius. Hair worms with the hinder end spirally 

 rolled and not forked in the male, but not rolled and with a knob-like 

 posterior swelling in the female: 5 species. 



* See "Observations on the Natural History of the Gordiacea," by J. Leidy, 

 Proc. A. N. S., Phila., Vol. 5, p. 262. "The Adult Organization of Paragordius varius 

 Leidy," by T. H. Montgomery, Zool. Jahrb., Vol. 18, p. 387, 1903. 



