56 COOK 



Gonapods short, both branches simple; antennae shorter than width 



of body. 



Gonapods with two slender prongs of nearly equal size and length ; 

 dorsum strongly convex, the carinae inserted at or below the middle 



line of side Genus Isaphe. 



Prongs of gonapods very unequal ; dorsum moderately convex, the 



carinae inserted above the middle line of side. 

 Posterior (lateral) branch of gonapod long, strongly curved, terete, 

 tapering to a slender point ; posterior corners of carinre rounded. 



Genus Hybaphe. 



Posterior branch of gonapod falcate, the apex broad and flattened ; 

 posterior corners of carinae distinctly angled. 



Genus Harpaphe. 

 Chonaphe gen. nov. 



Type. Chonaphe armata (Harger) from Oregon, Washington, 

 and Idaho. 



Body rather small and slender ; dorsum moderately convex ; carinae 

 inserted higher up and less thickened on the margin than in related 

 Western genera. 



Antennae filiform, longer than the body is wide ; legs also long and 

 slender in comparison with those of related genera. 



Gonapods much longer than in allied forms, the laminate-cristate 

 anterior branch much larger than the slender and strongly incurved 

 posterior branch. 



CHONAPHE ARMATA (Harger) . 



(pi. iv, figs. 2a, 2b, 2c.) 



Polydesmus armatus HARGER, Am. Jour. Sci. and Arts, iv, p. 120, July 13, 



1872. 

 Leptodesmus armatus BOLLMAN, Bull. 46, U. S. Nat. Mus., p. 122, 1893. 



A specimen apparently referable to this species is included in a col- 

 lection of Washington Myriapoda. 1 In addition to the characteristic 

 gonapods there are other conspicuous differences. In habit it is a slen- 

 der, long-legged animal. The dorsal convexity is moderately strong, 

 but the carinse are inserted higher up and are thinner than in the related 

 Western genera. The color of the alcoholic specimen is a uniform dull 

 purplish. It measures about 30 mm. by 4.5 mm. ; antennae 5 mm. ; 

 leg 4.2 mm. Harger's measurement is 28 mm. His specimens were 



States in the very flat dorsum, the thinner margins of the carinie, and the very 

 small last segment. The habit is also characteristic, the carinae being nearly as 

 continuous as in the Xystodesmidze. The femora are unarmed. 



1 Through the kindness of Prof. C. V. Piper, of Pullman, Washington, I have 

 recently received a small but very interesting collection of Myriapoda. 



