22 THE CANADIAN ENTOMOLOGIST 



Paratypes. — cfs and 9 s, from Victoria and Coldstream, 

 B.C., in colls. Blackmore, Barnes and Swett. 



These closely allied species are best separated by the geni- 

 talia, as the markings run very close and they are rather variable. 



Xanthorhoe pontiaria differs from the others in the shape of 

 the costa of the valvse, near the tip, which is somewhat sickle 

 shaped and has heavy, tooth-like spines resembling a lobster claw. 

 The sacculus is long and jointed, the saccus does not taper but 

 is broad and rounded at base. The penis is stout with a spined, 

 bulbous head, the spines being long and heavy. The calcar is not 

 heavily haired. 



Xanthorhoe macdunnoughi has a very short, chunky costa, 

 with deep sinus near the tip, which is heavily armed with fine 

 spines, extending around tip almost to the indentation on the 

 sacculus. The sacculus is not elongated as- in pontiaria and has 

 the indentation opposite projection of costa above, and is ^'ery 

 broad and somewhat angulate near the base. Penis stout with 

 bulbous spined head; calcar with fine, short hairs. The saccus 

 is not blunt but rather long and tapering. The shape of the 

 saccus alone would separate these two species. 



In Xanthorhoe blackmorei and the two species following, the 

 costa of the valvae is of a very different shape. About half way 

 between the tip and base there arises a jointed projection like the 

 horn of a rhinoceros, with the point directed just above base of 

 uncus. On the outer side it slopes down forming a sinus, the 

 extreme tip of costa being club shaped and with a few fine spines. 

 The sacculus is elongated, rounded at tip, and has very slight 

 indentation opposite base of projection. Near the base it forms 

 quite a sharp angle. The calcar is longer haired than the former 

 species and rather coarse. The saccus is broad and blunt like 

 pontiaria at tip. 



Xanthorhoe atlinensis shows a close relationship to black- 

 morei in the shape of the costa of the valvse but differs as follo.ws: 

 The projecting horn is a little nearer base and just before it there 

 arises a second little horn. The horn is more erect than in black- 

 morei and on the outer side slopes down, forming a gentle elongated 

 sinus, the tip of it being just rounded, not swollen or club shaped. 

 The sacculus is elongated and pointed at tip, and opposite the 



