412 THE CANADIAN ENTOMOLOGIST 



merit and not reaching as far back as tip of superior ap- 

 pendage; eyes moderately prominent 4 



3. Lateral spines of seg. 8 scarcely twice, those of seg. 9 2]/^ times, 



as long as their basal breadth, outer margins of latter dis- 

 tinctly incurvate; lateral appendages half as long as the 



inferiors, the latter not acuminate semicinctum 



Lateral spines of seg. 8 more than twice, those of 9 three times, 

 as long as- basal breadth, outer margins of latter nearly 

 straight, lateral appendages, less than half as long as the 

 inferiors, the latter apically acuminate viciniiyn 



4. Lateral spines of seg. 9 not less than two-fifths as long as the 



lateral margin of the segment, dorsal hooks well developed, 

 slender and very acute, that of seg. 7 nearly as long as the 

 mid-dorsal line of the segment, that of 8 usually more than 



half as long as the segment 5 



Lateral spines of seg. 9 not more than one-third as long as 

 the lateral margin of the segment, dorsal hooks smaller 

 and when well developed somewhat stouter and distinctly 

 curved, that of seg. 9 distinctly shorter than the segment, 

 that of seg. 8 rarely half as long as the segment 6 



5. Base of mentum of labium distinctly broader than middle 



coxae and som.ewhat more than one-fourth the greatest 

 width ; lateral spines of seg. 9 usually at least half as long 

 as lateral m.argins of the segment; lateral setae typically 



11 costiferum 



Base of mentum of labium scarceh', if at all, broader than 

 middle cox?e and about one-fourth of the greatest width, 

 lateral spines of seg. 9 two-fifths to one-half as long as 

 lateral margins of the segment; lateral setae typically 

 10 palUpes 



6. Dorsal hooks present on segs. 4 to 7 or 8, sometimes absent 



from seg. 4 or 8, lateral spines of seg. 9 about one-third 

 as long as the lateral margins of the segment, lateral setae 



9 to 11 7 



Dorsal hooks' present on segs. 5 to 7 only, vestigial, or absent 

 a-ltogether, lateral spines of seg. 9 about one-fifth as long 

 as lateral margins of the segment, lateral setae usually 

 11 rubicimdnlum decisnm 



