184 



CERASCOPUS, Heinek. 



172. C. errabundus, Say. 



Rare. Lancaster and Ridgeway, Ont., on pine trees in 

 August. 



FAMILY HYDROBATIDJ:. 



HYGROTRECHUS, Stal. 



173. rf. remigis, vSay. 



Rare. Colden, July 1885. 



LIMNOTRECHUS, Stal. 



1 74. L. marginatus, Say. 



July to Sept. Common everywhere on running water. I 

 have taken the young of this species during July and the 

 adult in January. 



LIMNOPORUS, Stal. 



175. L. rufoscutellatus, Latr. 



Another common species, especially on stagnant water in 

 ponds and ditches. 



FAMILY VELIID^E. 



HEBRUS, Curtis. 



1 76. H. americanus, Uhler. 



.Sometimes quite abundant on the surface of the water and 

 on wet slaty rocks in the gorge of Pipe Creek near West Falls, 

 Erie Co., in July and August. It could doubtless be found in 

 similar cool shaded ravines elsewhere in our district. This is 

 an active species and very difficult to capture. The fully 

 winged examples are rarely taken here. 



177. H. pusillus, Burm. 



A few specimens of this neat little species were taken on th« 

 moist sand among rushes along the edge of Cayuga Creek, at 

 Lancaster Village, July 12th, 1889. 



MESOVELIA, Muls. 

 17S. M. bisignata, Uhler. 



September. Taken with the nymphs in "The Bay" at the 

 upper end of Squaw Isd., Niagara River. Very few macrop- 

 terous examples were seen. 



RHAGOVELIA, Mayr. 

 178^. R. obesa, Uhler. # 



Taken by Mr. Frank H. Zesch from a small pool on the 

 borders of Niagara River above the rapids, at Dufferin Island, 

 near Chippewa, Out., Aug. 15, 1894. They were present in 

 numbers and very active, skipping about on the surface of 

 the water. 



FAMILY SALDID^E. 



SALDA, Fabr. 

 179. S. ligata, Say. 



Taken occasionally along the shores of Lake Erie and 

 Niagara River, from July to Sept, 



