303 



which I uave prepared will show the prevailing characteristics of this 

 iuteresting creature, its general ovoid and flattened form, and more 

 particularly the flattened semicircular head. Dorsally, we notice the 

 rather prominent occiput fringed behind with short and broad de- 

 pressed spines or teeth which form a sort of comb, the prothorax trapez- 

 oidal and but very slightly curved, with side margins strongly grooved. 

 There is a very distinct sciitellum, and the two elytra are rounded at 

 the tip and without venation. Hind wings and eyes are both wanting. 

 The abdomen shows five segments, each with a row of depressed bris- 

 tles. 





Fig. 67.— Full grown larvaof Tlaty- 

 psylldS crt«toris— dnrsa Iview — greatly 

 enlarged (after Riley). 



Fig. 68. — Platypsyllus castoris, adult — greatly 

 enlarged (after Kiley). 



On the ventral surface we find among the more curious characteris- 

 tics, first the anteunte; these were originally described by West wood 

 as three jointed, the club being annulated. Le Conte could not dis- 

 tinctly make out the number of annular joints upon this club, though 

 he thought he detected seven, which made nine joints to the whole an 

 tenna. The club is received in the deep cup-shaped excavation of the 

 second joint. Horn thought he detected a division of the second joint, 

 and resolved but six segments in the club, making also nine joints to 

 the whole antenna, but in a somewhat different fashion from Le Conte. 

 Westwood's figure shows eight annuli to the club. He failed to find 

 any trace of the mandibles, but Le Conte described them as small, flat, 

 subquadrate, with the inner side deeply crenulate, and resembling those 



