PLATYPSYLLIDAE. 75 



Mctatliorax short; inctasternum covei'cd in front by tliu 

 process of the rnesostcrnuiri, produced behind into u similar 

 process, fringed with long hair, and projecting over the 

 articulation of the thighs; side pieces large, transverse 

 oblique. 



Elytra not longer than the prothorax, trnncatc, and ' 

 broaxlly rounded at tip, slightly imbricate at the suture, 

 entirely without veins, except the usual subsutural one; 

 e[)iplur8e not separated by a line, but with a series of large 

 punctures along the lateral margin. Five dorsal segments 

 and the angles of the one anterior to them are exposed. 

 Wings wanting. 



Abdomen : dorsal surface flat, segments not margined at 

 the sides, each with a transverse row of small depressed 

 bristles ; spiracles near the hind angles of each segment, 

 equidistant from the lateral and posterior edges ; ventral 

 segments slightly convex, six are visible behind the coxse, 

 wliicli conceal two and the base of the third. Ventral seg- 

 ments straight, except the last two, which are curved, with 

 the convexity forwards; last segment feebly bisinuate at tip. 



C()Xi;e flat, not at all prominent; front ones snudl, sub- 

 triangular with rounded angles ; middle coxas similar, but 

 larger; hind coxiB very large, extending to the sides of the 

 body, flat. 



Legs short, trochanters not prominent, thighs stout and 

 compressed; tibiae compressed, triangular, rounded at tip, ^ 

 armed externally with long spines; terminal spurs long, 

 slender; front tibias shorter and broader than the others, 

 being only one-third longer than wide; hind til)i;o more 

 than two and a half times longer than wide, with two small 

 additional spines on the inner edge, above the terminal 

 spurs. Tarsi 5-jointed, slender, somewhat compressed, a 

 little longer than their respective tibiee; last joint one-half 

 longer than the fourth, claws simple. 



Bodv ovate, elongate, depressed, resembling in miniature 

 a Blatta. 



One represontativc only is known, Flafi/p.-^i/lhi. caMorix Ritsmna, 

 parasitic on the beaver. 



Dr. Lc Conte has fully discussed the complex relation.-^hips of 

 this sing:ular insect, in an illustrated memoir (Proc. Zoo). Soc. 

 London, 1872, 799; pi. l.wiii). U is also well figured by West- 

 wood (Thesaurus, 194, pi. 37),. who, however, considers it as 

 representing a distinct order, Achreioptera. 



