310 MICHIGAN SURVEY, 1908. 



parent, but the specimens with the fifth posterior cell uniformly infus- 

 cated at its base are usually decidedly larger than the others. This is 

 quite noticeably in the Isle Royale specimens. The type locality for the 

 species is the Lake Superior region, therefore these specimens should be 

 and are very nearly typical. Specimens of carhonarius from farther 

 east usually have a distinct hyaline spot at the base of the fifth pos- 

 terior cell and therefore are easily known. 



6. Chrysops frlgidus Osten Sacken. A single specimen taken Au- 

 gust 7, by B. F. Savery (V, 3) answers the description of this species 

 very well. Here the abdomen is variable in .coloration in a series of 

 specimens, but the wing markings are nearly constant. I have never 

 observed or heard of the species being so abundant and troublesome as 

 other members of the genus. Type locality Great Slave Lake and other 

 northern regions, but it is now known from as far south as Ohio and 

 New Jersey. 



Tabmius affinis Kirby. Taken July 2, on Mackinaw Island, Michigan. 

 A species with hairy e,yes, measuring nearly 20 millimeters in length, the 

 abdomen is broadly red on the sides and the palpi are long and slen- 

 der. The type locality is Boreal America and the species may be 'ex- 

 pected anywhere from Maine to British Columbia. This specimen is 

 typical for the species. 



7. Tdbanus epistatus Osten Sacken. Three specimens taken at 

 Light-house clearing (1,7) July 8, 11 and 31. Similar to the last in 

 coloration and general appearance, but smaller and the palpi are ro- 

 bust. Type locality Hudson Bay Territory, but now known to be 

 widely distributed in northern United States and Canada south to Ohio 

 and New Jersey. 



8. Tahanus lasioplitlialmus Macquart. A single specimen taken at 

 Eock Harbor, in July, by Adams. The eyes are hairy, the abdomen is 

 red on the sides and the size is near that of epistatus. The cross*-veins 

 are margined with fuscoiis making the wings appear spotted, a char- 

 acter which serves to separate it from epistatus and most other north- 

 ern species with hairy eyes. Type locality Carolina, but it is dis- 

 tributed over northeastern North America south to Georgia and west 

 to Illinois. 



9. Tahanus nivosus Osten Sacken. Several specimens taken at 

 Light-house clearing (I, 7) July 11, 26 and 28; (V, 3) August 7 and 9. 

 Length about 15 millimeters with a row of large white blotches or 

 spots on each side of the abdomen; wings clear hyaline; general color 

 blackish. Type locality New Jersey, and known from New York and 

 Ohio. 



10. Tahanus sp. Specimens taken at Light-house clearing (I, 7), 

 July 18 and 22. This, I take it, is a distinct species but it may be 

 one of Walker's obscure forms and I hestitate to name it specifically 

 until more material is available. The size is near that of nivosus, but 

 the general color is reddish, and the white markings on the sides of the 

 abdomen are not so conspicuous. There are a number of other char- 

 acters which distinguish it. 



11. Tahanus illotus Osten Sacken. Specimens taken at Light-house 

 clearing (I, 7), July 7, 11 and 25; and (III, 3), July 14, and August 

 5. Eyes hairy, abdomen with a row of white spots on each side, wings 



