108 Illinois State Laboratory of Natural History. 



tuberculate, and armed at apex with short, blunt 

 spines. Last segment of outer ramus armed with a 

 short blunt spine and a very long spinulose one. 



clavipes. 



3 (2). Antepenultimate article of right antenna without 



hyaline lamina. 



4 (5,10). Inner ramus of right fifth foot not reaching end of 



first segment of outer ramus ; sharply pointed. First 

 segment of outer ramus with hyaline lamina. Marginal 

 spine below middle of segment ; less than half as long 

 as segment. Terminal hook longer than the two pre- 

 ceding segments. Left leg extending slightly beyond 

 end of first segment of outer ramus of right leg ; inner 

 ramus reaching slightly beyond end of first segment of 

 outer ramus, indistinctly 2 -segmented, apex bluntly 

 rounded. tyrrelli. 



5 (1,10). Inner ramus of right fifth foot reaching end of first 



segment of outer ramus. 



6 (7). Inner ramus of left fifth foot extending to base of 



second segment of outer ramus, or slightly beyond. 

 Marginal spine below middle, near apical angle; less 

 than half as long as segment. Terminal hook at least 

 as long as the two preceding segments. Left leg reach- 

 ing about to middle of second segment of outer ramus of 

 right leg. Last segment of outer ramus armed with 

 forcipate structure ; inner digitiform process armed 

 with cushion on inner margin. pallidus. 



7 (6). Inner ramus of left fifth foot reaching to middle of 



second segment of outer ramus. 



8 (9). Marginal spine of right leg above middle of segment, 



very stout, as long as or longer than segment. Term- 

 inal hook almost as long as the two preceding segments 

 and second basal segment taken together. Inner ramus 

 as long as first segment of outer ramus. First seg- 

 ment of outer ramus with broad hyaline lamina on 

 inner margin. Left leg not quite reaching middle of 

 second segment of outer ramus of right leg. birgei. 



