Occasio)ial Papers of the Miisciiin of Zoology 13 



suture; these diverging bands vary considerably in intensity in 

 different specimens. The abdomen is slightly more narrowed 

 behind than in typical rilcyi, but the structure of the antennae 

 and the hind legs of the males is the same in both forms. 



In my collection I have Michigan specimens of Mctrobatcs 

 licspcriiis Uhler and Trcpobatcs pictiis (Herrich-Schaeffer), 

 two halobatine species which are widely distributed in Xorth 

 America, and they may possibly occur in this vicinity. 7'. 

 pictiis is lacustrine in habits, and is found both on the open 

 water of large lakes and on sheltered coves ; and M. hcspcrins, 

 while usually found in the same situations as that species, is 

 also found occasionally on slow-flowing rivers. 



Family \'euidae^ the Broad-Shouldered Water-striders. 



Key to the Genera of Veliidae of the Douglas Lake Region 



Fourth antennal segment longest; last segment of middle tarsi 

 deeply cleft, the cleft set with feathery hairs; hind femora 

 incrassate and spinose Rhagovelia 



First antennal segment longest [NIicrovelia 



Genus Rhagovelia jMayr 



7. Rhagovelia obesa Uhler. Apparently rather rare here. 

 The only specimens taken within our limits were collected on 

 Alaple River in August, 1914. Miss Butler secured about half 

 a dozen specimens on August 3, 1918, on a small stream about 

 fifteen miles west of Mackinaw City, in Emmett County, where 

 they were found in company with Gcrris reiiiigis. 



Genus ]\Iicrovelia Westwood 



8. Microvelia borealis Bueno. Common. This species was 

 most abundant at Bryant's Bog (Sta. IX), under the over- 

 hanging Chamaedaphne around the margins of the pond. At 



