Occasional Papers of flic Aliisciiin of Zoology ii 



2. Gcrris rciiiifjis Say. Found commonly in groups num- 

 bering about six to ten individuals on the back-eddies of the 

 streams. Xymphs were found abundantly in company with 

 the adults through July and August. A single specimen was 

 taken on standing water at Station IV on July 7, iyi8; and 

 two winged specimens were secured on Maple River on July 

 II. 



3. Gcrris inanjiuatits Say. This water-strider was found 

 on all the beach pools, bogs, and sheltered portions of Douglas 

 Lake, and also occasionally on back-eddies in the streams, and 

 among bulrushes on more exposed parts of the lake. Though 

 often taken at the same stations as G. biiciwi, it was seldom 

 found with that species, as it seemed to prefer more open 

 water, while hiienoi occurred most commonly among the veg- 

 etation. Brachypterous individuals were fairly common on 

 Sedge Pool (Sta. M) during July, but apterous individuals 

 were rare. 



4. Gcrris hiicnoi Kirkaldy. The most abundant and widely 

 distributed waterbug of the Douglas Lake region ; found at all 

 the stations except the rapid streams arid the exposed situa- 

 tions on the large lake. Its habitat preferences have been men- 

 tioned under the preceding species : this was the only water- 

 strider found commonly among Scirpus and Carex at the 

 various pools. 'Apterous specimens were fairly common at 

 Station \l during July, and two pairs of apterous adults were 

 taken in copula, but no brachypterous individuals were observ- 

 ed. 



5. Gcrris rufoscutellatns Latreille. Less abundant than the 

 two preceding species^ but somewhat more common than G. 

 reniigis. The species was found at all the stations except the 

 exposed parts of the large lake. On the pools and bogs it 

 occurred in the same situations as G. marginal us, and, while 



