14 THE CANADIAN ENTOMOLOGIST. 



I observed in a number of specimens I succeeded in raising from the 

 ovum, some carried through to maturity, others Hving only through a few 

 instars. The life-cycle can therefore be completed in from 25 to 35 

 days. This would give from three to five broods in the course of the 

 summer, which must be the case, as young and old adults and nymphs rii 

 several stages can be found together at almost any time during the warm 

 weather. The nymphs in a general way resemble the adults, except that 

 they are a light green, save where tlie stomach contents show through the 

 transparent integument. They have a way of carrying the abdomen 

 turned up somewhat as do certain Staphylinds among the Coleoptera. 

 When fresh after reaching maturity, they are covered with a grayish 

 pruinosity. This frail little bug is long-lived too. Under favourable 

 circumstances they live at least a year. The individuals I observed were 

 of last year's broods and they survived in my aquaria until late in August, 

 when they died of old age, the last one being a male, which gave up the 

 ghost on the last day of the month. 



Mr. Martin to the contrary notwithstanding, I have found no difficulty 

 in breeding Hydrometra Martini in my aquaria. I kept the mated adults 

 in a large aquarium and by preserving the inner surface of tlie glass above 

 the water clean and polie^hed, they were prevented from getting a foothold 

 to aid them in climbing out and escaping. Their ova were deposited on 

 the sides of the aquarium, and the young emerged without any mishap. 

 For their comfort, a few pieces of duckweed afforded them a resting place, 

 although they seemed to prefer to cling to tlie sides of the aquarium or to 

 climb up a little way from the surface of the water, holding on to the 

 roughness caused by the coating or sediment left on the glass by the 

 water as it evaporated and became lower in the vessel, or where it had 

 splashed in moving the aquarium about. They are sufficiently hardy to 

 have survived two trips of a couple of hours each, confined in a collecting 

 bottle tightly closed. For food, tiies were the staple, with an occasional 

 mosquito or other soft-bodied insect by way of change. I think that with 

 ordinary care a very complete life-history could be worked out in an 

 aquarium. The only species of Hydrometra recorded from the United 

 States is Hydrometra Martini, Kirk, Close collecting may eventually 

 show others, especially along our southern border, in Texas, Arizona, etc. 

 In facf. Say in his original description oi Hydrometra I itieat a noiQ?, a form 

 that he calls "var. ausiralis," from Louisiana. It has been my good 

 fortune to receive from Georgia, near the Florida line, one specimen 



