156 AGRICULTURAL EXPERIMENT STATION. 



21. Moderate-sized species, 22- 



Very large larva ; scales 28-34, with long apical and slender 



lateral spines; siphonal spines 17-22, with 4 or 5 large 



teeth basally, C. squainigcr 



22. Scales 25-30, with short apical and very short lateral spines ; 



siphonal spines 16-20, with i or 2 teeth at base, i 



usually very large, C. preians 



Scales 40-45, with 5-7 large apical and smaller lateral spines ; 

 16-22 siphonal spines, with usually i or 2, rarely 3 

 or 4, small teeth C. hiconspicnus 



Scales 45 (one larva), with small, slender, apical and fine 

 lateral scales; 15-27 siphonal spines, with 1-3 large 

 teeth ; rust-colored marks on thorax, C. nivcitarsis 



Scales 25-50, with small apical and smaller lateral spines ; 

 16-24 siphonal spines, with 4-5 serrations on basal 

 half ; antenna dark at tip, C. canadensis 



23. Antenna arising from an offset 24 



Antenna not arising from an offset, tuft below the middle : 



scales 24-30, C. siphonalis 



24. Antennal offset and tuft well above the middle, 25 



Antennal offset and tuft below the iniddle ; siphon of mod- 

 erate length; tracheal gills rather long C. restnans 



25. Anal siphon of moderate length, sides a little inflated ; 



tracheal gills moderately long, C. pipicns 



Anal siphon very long, rather slender, tapering regularly to 

 tip ; head narrower than thorax ; tracheal gills short, 



C. saliuarins 

 Anal siphon very long and slender, a little constricted cen- 

 trally; head as wide as thorax; tracheal gills mod- 

 erate or long, C. territans 



26. A bronzed brown larva with rather long, moderately stout 



black breathing tube, C. mclaiiiti us 



Note concerning illustrations. — In all the plates showing larvae 

 the drawings have been made under the microscope, in large part 

 from cast skins, for details. The result is that the anal siphons 

 are, in almost every instance, too broad, and in any measure- 

 ments one-fourth of the width should be deducted. The larval 

 heads are also from cast skins. Except where otherwise credited, 

 the original drawings are by Mr. Grossbeck, and on those figures 

 credited to Mr. Joutel the adults only were drawn by him, the 

 details supplied later by Mr. Grossbeck. 



