112 Illinois State Laboratory of Natural History. 



30 ("29). Process extending very slightly beyond end of article 



of which it is a part. Hyaline lamina extending entire 

 length of segment. 



31 (32). Inner ramus of right leg reaching well beyond mid- 



dle of the very long first segment of the outer ramus. 

 Marginal spine below middle, near apical angle ; less 

 than half as long as segment. Terminal hook shorter 

 than the preceding segment. Left leg (excluding ter- 

 minal spines) reaching about to middle of first segment 

 of outer ramus of right leg. Last segment of outer 

 ramus terminated by two spines ; inner ramus reach- 

 ing well beyond end of first segment of outer ramus, 

 but not to middle of last segment. leptopus. 



32 (31). Inner ramus of right leg rudimentary (the suture 



being rarely visible), barely reaching the end of the 

 very short first segment of the outer ramus. Marginal 

 spine below middle of segment, less than half as long as 

 segment. Terminal hook stout, longer than the pre- 

 ceding segment. Second basal segment very broad, 

 armed at outer distal angle with a process about as 

 large as the inner "ramus." Left leg very short, barely 

 reaching end of second basal segment of right leg; 

 inner ramus very short, extending barely beyond end 

 of first segment of outer ramus. sanguineus. 



33 (28). Process not the continuation of a hyaline lamina. 



34 (41). Process straight. 



35 (36). Process serrate on outer margin, extending beyond 



middle of penultimate article. Inner ramus of right 

 leg very broad and short, extending but slightly be- 

 yond middle of first segment of outer ramus. Margi- 

 nal spine above middle of segment, less than half as 

 long as segment. Terminal hook longer than the very 

 long preceding segment. Left leg very short, extend- 

 ing barely beyond end of first segment of outer ramus 

 of right leg. First basal segment of both legs with 

 long slender spine on posterior surface. trybomi. 



36 (35). Process not serrate. 



