248 



BULLETIN OF THE BUREAU OF FISHERIES. 



More than two-thirds of the insects eaten by the baldpate (0.29 per cent of the whole) were beetles. 

 These included water scavenger beetles (Hydrophilidse), found in 8 stomachs, predacious diving beetles 

 (Dytiscidse), in 2, * * and unidentified fragments of beetles in 16 [p. 15]. 



Those [beetles] most commonly taken [by the green-winged teal] were predacious diving beetles 

 (Dytiscidse), water scavenger beetles (Hydrophilidse), crawling water beetles (Haliplidse), snout beetles 

 and other weevils (Rhyncophora), and ground beetles (Carabidse) [p. 21]. 



Beetles (Coleoptera) amounted to 2.62 per cent of the food of the blue-winged teal, or less than 

 one-tenth of the total animal matter eaten. Ten species of predacious di\dng beetles (Dytiscidse) were 

 noted, five of water scavengers (Hydrophilidse), four of crawling water beetles (Haliplidse), * * *, 

 and one of whirligig beetles (Gyrinidse) [p. 27]. 



Over half of the insect food of the series of cinnamon teals (5.40 per cent of the whole) consisted of 

 beetles (Coleoptera). Disregarding several unidentified fragments, only four families were represented, 

 the predacious diving beetles (Dytiscidse), water scavenger beetles (Hydrophilidse), leaf beetles (Chry- 

 somelidse), and snout beetles (Curculionidse) [p. 30]. 



Beetles (Coleoptera), amounting to 0.93 per cent of the total food of the pintail, consisted largely 

 of three families, the predacious diving beetles (Dytiscidse), water scavenger beetles (Hydrophilidse), 

 and ground beetles (Carabidse) [p. 36]. 



Beetles of at least 15 families were represented in the food of the wood ducks examined. Of these 

 the water scavenger beetles (Hydrophilidse), predacious diving beetles (Dytiscidse), and leaf beetles 

 (Chrysomelidse) were most commonly taken. * *. Two other strictly aquatic families — the whirli- 

 gig beetles (Gyrinidse) and crawling beetles (Haliplidse) — were well represented. * * Peculiar 

 little silken cases containing eggs of water scavenger beetles, usually attached to a submerged leaf or to 

 the body of the female beetle herself, are not infrequently found in duck stomachs [p. 47]. 



TOADS AND FROGS. 



In discussing tlie natural liistory and utilization of frogs Wright (1920, p. 41) 

 made the following statement : 



Coleoptera, mainly ground, lamellicorn, and click beetles, and weevils constitute 27 per cent of 

 the food of the toad, while in the animal food of the leopard frog beetles form 33 per cent of the whole, the 

 principal groups being ground, tiger, and snout beetles. In the food of the wood frog, pickerel frog, 

 and green frog the proportion is equally large, while in the diet of the bullfrog the beetle element is 

 surprisingly large. No doubt water beetles of the surface enter into the food of the bullfrog more than 

 into that of the other species of frog. 



Of 10 leopard frogs (Rana pipiens)^ captured on the shores of the fish ponds 

 at Fairport in August, 1920, 8 had eaten adult water beetles, and 1 of the other 

 2 had eaten land beetles. Of 15 cricliet frogs (Acris grillis) captured at the same 

 time, every one had eaten adult beetles, and in the diet of 8 of them some form 

 of water beetle was included. The simple fact that beetles constitute so large a 

 percentage of the food of the toad and the various frogs indicates that all of these 

 batrachians probably eat water beetles whenever they get a chance. 



ELECTRIC LIGHTS. 



Reference has already been made under locomotion to the fact that the adult 

 beetles while migrating from place to place are often attracted by electric lights. 

 Although some escape this peril many fall beneath the lights into the dust and 

 perish. This is especially true of the larger species but applies also to the smaller 

 ones. Trap lanterns that are set for moths usually capture a considerable number 

 of water beetles, and the nearer to the water they are set the greater the danger to 

 the beetles. 



