188 THE CANADIAN ENTOMOLOGIST. 



a rudimentary eye barely visible ; maxillae not so rectangular as 

 in odactetws, somewhat obliquely cut off below ; pronotal comb 

 of 14 to 15 spines ; metanotum with 7 teeth on either side ; in 

 anterior tarsi joint i as long as 5, as long as 2 and as long as- 3 

 and 4 together, 5 is much the thickest ; in posterior tarsi joint 



1 as long as 2, 3 and 4 together, 2 as long as 3 and 4 together, 

 5 somewhat shorter ; length, 2-3 mm pentadenus. 



F. Abdomen with the seventh segment, only, comb-bearing ; length, 



2 mm dictenus. 



G. Head comb on anterior edge of antennal groove, the spines point- 



ing straight backward J. 



GG. Head comb in normal position on lower edge of cheeks, the 



spines pointing downward and backward H. 



H. Pronotal comb of 7 to 9 spines on either side ; head comb of 

 usually 3, sometimes 4, spines on either side ; with a very rudi- 

 mentary eye ; abdominal segments with 2 dorsal rows of 

 bristles ; in middle tarsi joint i equals 5 ; in posterior tarsi 

 joint I is one-third longer than 2 /. 



H H. Pronotal comb of r i spines on either side ; head comb of 4 

 spines on either side ; maxillas short triangular ; maxillary palj)i 

 • with joints of nearly equal length ; abdominal segments each 

 with one ventral and two dorsal rows of bristles ; legs with 

 numerous short spines ; in middle tarsi joint 2 is somewhat 

 shorter than i and somewhat longer than 5 j in posterior tarsi 

 joint I is a half longer than 2 ; colour, yellowish-brown ; length, 



2 mm . tiuisadi. 



I. Pronotal comb of 7 spines on either side; head comb of 3, some- 

 times 4, spines on either side ; maxillae long and acute ; male 

 claspers in the form of two long sugar-loaf plates; colour, pitch- 

 brown ; length, 3 mm caucasica.. 



H. Pronotal comb of 7 to 9 spines on either side; head comb of 3 



spines on either side ; male claspers boot-shaped, the sole turned 



up ; colour, dark brown ; length, 2.5 mm assimilis. 



J. Head comb of 4 spines ; the two upper spines of head comb 

 much longer than the lower ; pronotal comb of 9 spines on 

 either side ; proportions of tarsal joints as in caucasica ; male 

 claspers blunt, of the shape of a "ninepin or a cucumber " ; 

 colour, light brown ; length of male, 2-2 5 mm. ; of female, 



3 m in gracilis. 



