119 
is, which stand at thirty-six per cent. The pollen eaten by each 
ip was thirteen per cent.—the same in both. If we combine the 
collections, and treat the thirty-nine specimens of both as a 
le, we find that insect food is about a third of the entire amount, 
that the other animal elements are only trivial. The function 
le beetles of this family of limiting the multiplication of plant- 
is expressed by the fact that these insects compose a fourth of 
food of this entire collection. The pollen of grasses and Com- 
■ae make fourteen per cent., the spores of lichens four per cent., 
those of fungi nearly half the whole (forty-five per cent.)- 
SuFFICJENCY OF DATA. 
n. 
le food of the Coccinellidas seems to be, on the whole, remark- 
simple and uniform, consisting wholly of spores of the lower 
togams, pollen grains, and plant-lice, and varying but little from 
genus to another. This similarity is likewise reflected in the 
,th parts, which agree as closely in form and structure as do the 
s of the food. I have consequently little doubt that the data 
I ed from the thirty-nine specimens here discussed, will be found 
"lent for a correct general idea of the food of the family under 
iary circumstances. 
th respect to the Carabidae, we have other proof. In a brief 
;jr published by me in 1880, in Bulletin No. 3, Illinois State 
jjrafory of Natural History, based on an examination of only 
tty-eight specimens belonging to seventeen species, the conclu- 
Iwas announced that about one-half of the food of this family 
sted of vegetation, and one-third of insects; and the vegetation 
bought to be about equally divided between cryptogams, grasses 
L 3xogens. If these figures or those of the present paper were 
Tong, the probabilities would by very slight indeed that the two 
ates would agree, especially as no comparison whatever was 
of the two sets of data, until the tables were completed in 
present form. When, therefore, we find that the one 'hundred 
Jieventy-five specimens of the present paper, belonging to thirty- 
; species, were estimated to have taken fifty-seven per cent, of 
il food, and thirty-six'of insects, and that the ratios of crypto- 
graminaceous plants and exogens are respectively five, eleven, 
f ve, we must conclude that the above figures are a fair average of 
"rdinary food of the family. 
urring now and finally to the questions propounded at the 
f; encement of this paper,* we have to note the replies which the 
collected enable us to make. 
far as the Carabidse are concerned, the answer must vary 
ling to the genus and species—some being so far vegetarian 
bit that their function as checks upon insect life is only 
in importance. Respecting those which are to be properly 
d as insectivorous, it is plain from the foregoing data that a 
ensible effect must be produced upon already existing oscilla- 
So many species were found eating a great excess of cater- 
in the orchard where canker-worms abounded, that we cannot 
that they had been tempted from their usual regimen by the 
105 . 
i 
