THE CANADIAN ENTOMOLOGIST. 14-1 



blotting-paper and containing a few threads of excelsior and a little wad 

 of it at the bottom. 



The best aquaria are the ordinary round glass ones, or battery jars of 

 different sizes. For the Water-striders, those giving quite an extensive 

 surface of water are the best ; for the CryjUocerates, tiie water is better 

 deep. Microvelias can be very well kept in jelly-glasses or any other of 

 the thousand and one glasses or earthenware receptacles in which eatables 

 are put up; the shallower and wider-mouthed they are, the better. All 

 these aquaria must be covered with pieces of glass to keep dust from 



falling in and to j^revent the water from evaporating and the bugs from 

 escaping. The Velias should have Duckweed to rest on. The others 

 should have some sort of vegetation in the water, partly to preserve it 

 sweet, partly to give the swimmers something to cling to and on which to 

 deposit their ova, should they breed. For food, flies (Musca) answer every 

 purpose. It is better to feed them living or freshly caught, although the 

 iiungry bugs will feed on them even a day or two old. Just throw them 

 in and the bugs will do the rest. ON NO ACCOUNT FEED THEM 

 INSECTS KILLED IN THE CYANIDE BOTTLE. These are 

 deadly. Nor is it safe to put Water-striders in the same aquarium with 

 Notonectas, Nepa, Ranatra, Pelocoris or Belostomas of any kind. They 

 do not last long under these conditions. Neither should Notonectas and 

 Corixas be put together; nor, in general, any bug with others smaller. 

 The last will merely be a feast for the larger brethren. Even those of one 

 species will destroy each other when driven to it by hunger. 



The best times of the year to collect Aquatic Hemiptera are the 

 Spring and Fall. As soon as the ice disappears from the ponds and lakes 

 and streams, the larger Water-striders can be seen in abundance, the 

 Corixas and Notonectas arouse themselves from their Winter's sleep, and 

 Pelocoris, the Belostomas, Nepa and Ranatra leave their muddy Winter 

 quarters and once more actively commence the real business of life — the 

 propagation of their kind. From March until the end of May or the 

 beginning of June, over-wintering adults of all the species may be found. 

 After that, only the young abound, till August, when the season's brood of 

 adults begins to appear. Collecting now continues good until the water 

 gets too cold toward the end of Autumn. I have taken these families in 

 this latitude as early as the middle of February and as late as the end of 

 November. In the South, they are apparently obtainable at even later 



