50 NEUROPT-ERA OF NORTH AMERICA. 



short pile, a little longer than the body; feet whitish, femora with 

 a medial and apical fuscous band ; wings hyaline, veins fulvous ; 

 anterior ones with the apex of the costal margin fulvescent. 



Length of body 8 millim. Alar expanse 24 millim. Setoe 24 

 millirn. 



Hob. North America (Zimmerman) ; St. Martin's Falls (Barn- 

 ston). 



The specimens described by Mr. Walker are a female and sub- 

 imago, not males as Walker contends, and, perhaps, belong to a 

 different species; Burmeister's species is perhaps a subimago, and 

 it may be of the preceding species. 



17. B. basalis. 



Baetis basalis Walk. Catal. 565, 31. 



Pitch-black ; antennae whitish ; abdominal segments margined 

 with testaceous; seta? whitish, the incisures annulated with black, 

 twice as long as the abdomen ; anterior wings hyaline, the costal 

 veins clouded with fuscous, a middle marginal fuscous nebula; pos- 

 terior wings fuscous, their apex hyaline. (From Walker's descrip- 

 tion.) 



Length of body 12 millim. Alar expanse 28 millim. Seta3 22 

 millim. 



Hob. Lake Winnipeg (Richardson). Is it not B. luridipenms? 



18. B. noveboracana. 



Ephemera noveboracana Liclitenstein, Catal. Mus. Holtliuisen 1796, III, 

 193, 52. 



Bisetousj wings fuscescent, the hind ones smallest; the abdomen 

 fuscous, margined with luteous. (From the description of Lichteu- 

 stein.) 



Hob. New York. Is it not B. luridipennis? 



19. B. tessellata! 

 Baetis tessellata Hagen ! 



Luteous ; mesothorax each side with a fuscous line ; abdomen, 

 upon the segments, superiorly each side, with two fuscous triangu- 

 lar spots; seta? ? feet luteous, tarsi at the apex fuscous; wings 

 opaque, gray, ciliated, veins lurid, many quadrangular, hyaline 

 spots, posterior wings very small. Female, subimago. 



Length of body 16 millim. Alar expanse 26 millim. 



