68 
baking-powder, and snuff. Corn and wheat are also often infested 
by it, beetles and larvae feeding upon the grains together, the 
former, in fact, being perhaps more destructive, and certainly more 
active, than the larvae. 
This species occurs all over the United States, and is cosmo¬ 
politan in its range. 
Another beetle, called the rust-red flour-beetle ( Triboliiun fer- 
rugineum Fabr.), less common than’the preceding, is often found 
with it, being similar to it both in habits and in appearance. It 
is specifically different in the shape of the head and the terminal 
joints of the antennae. It is also more southern in its distribution. 
These insects may be killed in the grain by the use of heat, or 
by fumigation with insecticide vapors, as is elsewhere described; 
and all valueless infested material should be gathered up and 
burned. 
The Saw-toothed Grain-beetle 
(Silvanus sarinamensis Linn.J 
A minute, flattened, chocolate-brown beetle, with the margins 
of its thorax roughened with toothlike projections, if found 
abundant in groceries or other edible substances, may be assumed 
to be this grain-beetle. The slender adult is not more than a tenth 
of an inch long. The thorax is marked with two longitudinal 
Fig. 9 - Saw-toothed Grain-beetle, Silvanus surinamensis: a. adult; 
b, pupa, under side; c, larva. Enlarged as indicated. 
(U. S. Dept, of Agriculture.) 
grooves, one on each side, and with six minute teeth, like those 
of a saw, on each lateral edge. The head and thorax are densely 
covered with fine punctures, and the wing-covers are finely punc¬ 
tured and lined. The larva is somewhat flattened, with transverse, 
