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Food of the Adult. ' 
The twenty-four adults examined were from various parts of the 
State north of the center; and, as the food has been found to differ 
‘so widely according to the local situation, I have treated them in 
three groups,—-the first including those taken in the clear, inland, 
northern lakes; the second those from Calumet River, at South 
Chicago, and the shallow, muddy lakes of that vicinity, and the 
third those from the Illinois river, from Ottawa to Peoria. . 
The specimens from the northern lakes were taken in May and 
June. Sixty-two per cent. of the food consisted of Neuroptera,— 
eight per cent. being a black caddis-fly (Stalis infumata) and the 
remainder the larve of large dragon-flies (Libellulide), Agrions” 
(eleven per cent.) and Baétis (two per cent.). Allorchesies dentata 
was the next most important element (twenty-seven per cent.). A’ 
number of terrestrial insects besides Sialis appeared in the food. 
These included a harpalid beetle, an Aphodius fimetarius, and some 
grasshoppers (Tettigide, etc.). 
The second group, of four, from Calumet River, and from Lake 
George, Indiana, was peculiar in the number of tetradecapod 
Crustacea and case-worms taken, and especially in the amount of 
vegetation eaten. 
The crustacea were Allorchestes (thirty-two per cent.) and Asel- 
lus (twenty per cent.). The vegetation was present in such quan-_ 
tities as to make it evident that it had been taken as food. It 
amounted to about a fourth of the contents of these stomachs. 
The stomach of one fish was packed with a piece of the stem of a 
plant (apparently a Scirpus) a third of an inch in diameter and six 
inches long. Three others contained smaller amounts of confer- 
void Alge. 
The fifteen specimens remaining were taken from the Illinois in 
May, July, August, October and November. Their food was espe- 
cially noticeable for the presence of mollusks (sixteen per cent.), for 
the number and variety of land insects (fifteen per cent.), and for 
the large amount of vegetation it contained (thirty-one per cent.). 
A single small fish,—the only one taken by these forty-five speci- 
mens—was also noted. 
The mollusks included planorbis, Physa, Amnicola and Vivipara. 
Among the insects were ants, caterpillars, flies, Anzsodactylus dis- 
coideus and other harpalids, Aphodius inquinatus, wire-worms, 
minute Curculios, Cryptocephalus 4-maculatus, Diabrotica 12-quttata, 
Colorado potato beetles, flea beetles, plant bugs (Cydnide), 
crickets (Nemobius), locusts and katy-dids (Phaneroptera curvi- 
cauda), grasshoppers and caseflies. 
The vegetable food, as far as determined, consisted of Cerato- 
phyllum, Nais flexis and confervoid Alge. Fragments of Polyzoa 
were noticed. Coptotomus interrogatus, gyrinid larve,* Tro pisternus 
limbatus and other Hydrophilide,.larval and adult, a large Nepa, 
larvee of Palingenia bilineata and other May-flies, of Agrions and 
dragon-flies were among the aquatic insects taken. 
*Several of these little-known larve were found in the stomachs of this species,—— 
some of them in suitable condition for description. j 
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