362 CLAVICOKNIA — TRICHOPTERYGIDAE. 



2, Head large, elongate. 



Elongate oval, rather convex. Head and thorax chestnut- 

 brown ; elytra and abdomen reddish-yellow ; antennae and 

 legs yellow ; rather closely covered with short pale hairs. 

 Eyes small, placed very far back ; thorax slightly longer 

 and broader than head, rather strongly, closely tuberculate, 

 rather broad at base ; elytra longer than liead and thorax, 

 scarcely broad than latter, deeply and very closely 

 asperate in transverse rows, apices not strongly rounded ; 

 abdomen very obtuse ; legs long, robust. L. y^ 1. Eare. 



P. hritannica, Mat. 



II, Posterior angles of thorax prominent, very acute. 



Flat. Pale yellow ; rather closely covered with golden- 

 yellow hairs. Head broad and rather short ; thorax longer 

 and somewhat broader than head, broadest in middle, 

 somewhat constricted behind, moderately strongly tubercu- 

 late ; elytra slightly longer and broader than head and 

 tliorax, deeply and very diffusely asperate in transverse 

 rows, interstices slightly asperate, apices broad, not 

 strongly rounded ; abdomen moderately elongate, some- 

 what acute at apex. L. y%- 1. Rather common. 



P. denticollis, Fairni. 

 -B. Abdomen narrower, pointed at apex. 



a. Elytra longer than head and thorax. 



I. Thorax strongly constricted behind, posterior angles 

 prominent, acute. 

 Elongate, very narrow. Pale yellow ; covered with short 

 pale liairs. Head elongate ; thorax very short, nnich 

 sliorter than head, closely and very feebly tuberculate ; 

 elytra long and narrow, mucli longer and scarcely 1)roader 

 tlian head and thorax, nearly parallel-sided, feebly and 

 diffusely asperate, apices strongly rounded. L. y%- 1. Eare. 



P. tenella, Er. 



II» Tliorax not constricted behind, posterior angles 

 not prominent, nearly riglit angles. 



Elongate, oval, rather flat. Bright yellow ; legs and an- 

 tennae i^ale yellow ; closely covered with rather long pale 

 hairs. Head rather large, strongly rounded in front ; 

 thorax slightly longer and broader than head, closely, rather 

 feebly tuberculate ; elytra longer and broader than head 

 and tliorax, closely and rather strongly asperate, apices 



