BAETIS. 45 



I have seen a specimen (9 Imago) from the Vienna Museum; 

 it may be the one described by Pictet (although the setse are longer, 

 14 millim.). As that female pertains, undoubtedly, to B. inter- 

 punctata, probably, therefore, B. flaveola is nothing but a female 

 B. interpunctata Say. On account of a slight fold in the anterior 

 margin of the wings the submarginal line is seen with difficulty. 



I have seen a mutilated, smaller, female subimago from Ten- 

 nessee (with the wings expanding 18 millim.), which may be a dis- 

 tinct species. 



3. B. obesa. 



Baetis obesa Say. Journ. Acad. Philad. VIII, 43, 4. Walk. Catal. 563, 26. 



Subimago. Black, livid ; wings brownish-black, with many small, 

 transverse hyaline spots or abbreviated lines, a large, hyaline, 

 oblique semifascia about the middle on the anal margin ; posterior 

 ones, with many transverse, abbreviated, hyaline lines not attaining 

 to the apical margin ; feet pale yellow, incisures of the tarsi black; 

 abdominal segments margined with rufous; setse very short, pilose, 

 annulated with black. (From Say's description.) 



Length of body 8 millim. 



Hob. Indiana (Say). 



4. B. fusca! 



Baetis fusca Walker! Catal. 568, 38. 



Imago g 9. Piceous, beneath ferruginous; antennae black; 

 abdomen ferruginous, beneath fulvous ; setae testaceous, subannu- 

 lated with fuscous, three times the length of the body; feet testa- 

 ceous, the anterior ones fuscous; wings hyaline, anterior ones with 

 the costal margin at the apex fuscous. (From Mr. Walker's de- 

 scription.) 



Length of body 8 millim. Alar expanse 20 millim. Setaa 25 

 millim. 



Hob. St. Martin's Falls, Albany River, Hudson's Bay (Barn- 

 ston). 



I saw the specimen in London, and noted at that time that it 

 was closely allied to B. flaveola ; the specimen from Nova Scotia 

 belongs to P. concinnus Walk. Perhaps a. male imago, from 

 Washington (Osten Sacken), and one from Chicago, belongs here. 



