462 BULLETIN 63, UNITED STATES NATIONAL MUSEUM. 



external two-thirds, becoming continuous internally Avitli the inner 

 margin of the fossa. Apex produced and not everted, sides sub- 

 parallel, externally continuing the line of the dorsal plate, tip rather 

 broadly rounded, dorsal surface concave; internally the valvular 

 membrane is finely setose and semi-chitinous caudad to the pudendal 

 membrane. 



Appendage short and nearly hemispherical, projecting very little 

 beyond the fossa, setose at tip, setic long forming a loose pencil. 

 Fossa rather broad and not sharply defined. 



SKperior pudendal memhrane reaching to the apical fourth of the 

 dorsal plate and longitudinally rugulose. 



Basal prominences scarcely at all prominent. 



Yentrolaferal sifrfares transversely convex, surface lines straight 

 when vieAved longitudinally, concave apicall}' before the apices. Sub- 

 marginal groove distinct beneath the feebly explanate external margin 

 of the dorsal plate. Internal margins of the valves contiguous in 

 basal two-thirds ; genital fissure very narrow in apical third. Inferior 

 membrane not visible. 



Hahitaf.—New Mexico (Cloudcroft, elevation 9,000 feet). 



Number of specimens studied, 7 (females). 



Types in my own collection. 



Type-localiti/.- — Cloudcroft, New Mexico ; collector, Warren Knaus. 



Diagnostic characters. — The seven specimens studied are homomor- 

 phic and distinct from their congeners. The shortening of the ex- 

 panded pronotal margin is quite remarkable, and the basal constric- 

 tion causes the prothorax to appear more distant from the elytra than 

 in depressum . 



In fact, the form of the prothorax is an approach to that observed 

 in Eleodes planipennis. Contractum appears as a step toward the 

 bridging ovei- of the gap between Eleodes planipennis and Etn- 

 haphion. Tt is also significant that both should inhabit the same 

 geographical regioji. Some specimens of planipennis exhibit a ten- 

 dency to a thiiming and reflexion of the pronotal margins, but never 

 to an acuteness of the elytral margins. When such examples are 

 found planipennis must be referred to E/tibap/iion. 



In depressum the acute elytral margin attains the apex, in contrac- 

 tum it does not. 



In planum the acute and expanded pronotal margins reach to and 

 slightly beyond the base, while in contractum they are abbreviated 

 posteriorly and not extending beyond the basal se\ enth or eighth, the 

 true basal angles being exposed. 



Contractum is without doubt an extreme and peri)etuated modifi- 

 cation of planum. In the series of contractiim examined the abdo- 

 minal segments are not oblique. 



