The Food Relations of the Carabidce and Coccinellidce. 55 
the Coccinellidce themselves, the latter had reached an excessive 
number, for which the supply of plant-lice was really insufficient, 
and that for this reason they had resorted to fungi. 
The chinch-bugs taken by the specimens of the second group 
amounted to only eight per cent, of their entire food, and plant- 
lice to fourteen per cent., — less than half those taken by the other 
specimens, which stand at thirty-six per cent. The pollen eaten 
by each group was thirteen per cent., — the same in both. If we 
combine the two collections, and treat the thirty-nine specimens 
of both as a whole, we find that insect food is about a third of the 
entire amount, and that the other animal elements are only trivial. 
The function of the beetles of this family of limiting the multi- 
plication of plant-lice is expressed by the fact that these insects 
compose a fourth of the food of this entire collection. The pollen 
of grasses and Composite make fourteen per cent., the spores of 
lichens four per cent., and those of fungi nearly half the whole 
(forty-five per cent.). The list of genera, as far as recognized, 
and the relative importance of these, may be found by reference 
to the tables at the end of this paper. 
Sufficiency of Data. 
The food of the Coccinellidae seems to be, on the whole, remark- 
ably simple and uniform, consisting almost wholly of spores of 
the lower cryptogams, pollen grains, and plant-lice, and varying 
but little from one genus to another. This similarity is likewise 
reflected in the mouth parts, which agree as closely in form and 
structure as do the ratios of the food. I have consequently little 
doubt that the data derived from the thirty-nine specimens here 
discussed, will be found sufficient for a correct general idea of the 
food of the family under ordinary circumstances. 
With respect to the Carabidse, we have other proof. In the 
preliminary paper in Bulletin 3 already referred to, based on an 
examination of only twenty-eight specimens belonging to seven- 
teen species, the conclusion was announced that about one-half of 
the food of this family consisted of vegetation, and one-third of 
insects; and the vegetation was thought to be about equally divided 
between cryptogams, grasses and exogens. If these figures or 
those of the present paper were far wrong, the probabilities 
would be very slight indeed that the two estimates would agree, 
