FOOD HABITS OF SHOAL- WATER DUCKS. 21 



adept at fly-catching. The larvae of midges (Chironomidae) were 

 found in 61 stomachs, sometimes in very large numbers, and formed 

 the bulk of the dipterous food taken. They are abundant in shallow, 

 standing water and slow streams almost everywhere, feeding upon 

 decayed vegetable matter, and evidently are eagerly sought by the 

 ducks. The larvae and pupae of craneflies (Tipulidae), soldierflies 

 '(Stratiomyidae), and Ephydridae were also commonly taken. 



Although beetles (Coleoptera) formed only 0.65 per cent of the 

 total food, they were represented by a larger number of families and 

 genera than the flies. Those most commonly taken were predacious 

 diving beetles (Dytiscidae), water scavenger beetles (Hydrophilidae), 

 crawling water beetles (Haliplidae), snout beetles and other weevils 

 (Rhynchophora), and ground beetles (Carabidae). 



Next in order of importance in the insect food of this teal come 

 the bugs (Hemiptera), with 0.54 per cent, including both the true 

 bugs (Heteroptera) and the cicadas, leafhoppers, etc. (Homop- 

 tera). Of the true bugs, water boatmen (Corixidae) were found in 

 32 stomachs, sometimes in very large numbers; back swimmers 

 (Notonectidae) in 4 stomachs; water striders (Gerridae) hi 4; and 

 unidentified bugs in 6. The Homoptera were represented by a single 

 jassid, or leaf hopper. 



Caddisflies (Phryganoidea) furnished 0.31 per cent of the total food 

 of the birds examined. These were taken in the form of the larvae, 

 or caddis worms, which abound in creeks and ponds, or anywhere 

 in shallow water containing the vegetation upon which the fly lar- 

 vae feed. They live within silk cases or hollow cylinders made by 

 themselves and covered with a variety of materials, such as grains 

 of sand, bits of leaves or rushes, or pieces of mollusk shell. 'These 

 cases are open at each end, and the larva pulls itself along by means of 

 three pairs of legs which, with the head, can be protruded from one 

 end. Caddis larvae or cases were found in 46 stomachs, never in 

 very large numbers. 



The remaining insect food (1 per cent) was made up of damsel- 

 flies (Zygoptera), dragonffies (Anisoptera), stoneflies (Plecoptera), 

 bird lice (Mallophaga), grasshoppers (Orthoptera), ant-lions (Neurop- 

 tera), moths and butterflies (Lepidoptera), ants, bees, and wasps 

 (Hymenoptera), and a number of miscellaneous unidentified insects 

 and their eggs, pupae, and larvae. Probably the largest single item 

 among these miscellaneous orders of insects was the nymphs of 

 damselflies and. dragonflies, identified from 23 stomachs. 



MOLLUSKS (MOLLUSCA), 3.S9 PER CENT. 



Next to insects, mollusks furnished the largest item of animal 

 food for this teal, 3.59 per cent of the total. They were usually 

 found broken, although whole snails were sometimes present. Empty 



