16 
more often found in the open, but are capable of damage to stored foods 
if once they take up their habitation where these materials are kept. 
THE SAW-TOOTHED GRAIN BEETLE (Silvanus surinamensis Linn.). 
This little beetle is widely distributed over the entire globe, and of 
common occurrence In granaries and almost everywhere where edibles 
are stored. It is nearly omniverous, infesting grain, flour, meal, dried 
fruits and seeds of all sorts, breadstuffs, and other comestibles, and 
though usually following the attacks of other insects is often reported 
as doing considerable damage. 
The adultis very small, only about one-tenth of an inch long, slender, 
much flattened, and of a dark, chocolate-brown color. The antenn 
are clavate, or club-shaped, and the thorax has two shallow longitudinal 
grooves on the upper surface and bears six saw-like teeth on each side, 
as shown at fig. 15, a. 
The larva is nearly white, and, as will be noticed by reference to the 
illustration (¢), has six legs and an abdominal proleg. It is exceedingly 
active, and does not pass 
its life wholly within a 
singleseed, butruns about 
nibbling here and there. 
After attaining its growth 
the larva attaches itself to 
some convenient surface 
and constructs a covering 
by joining together small 
grains or fragments of in- 
fested material by means 
of an adhesive substance 
which it secretes, and 
Fia. 15.—Silvanus surinamensis: a, adult beetle; b pupa: c, within this case the pupa 
larva—all enlarged ; d, antenna of larva—still more enlarged (dD) and afterwards the 
(author's illustration). 
adult states are assumed. 
It is estimated that there are usually four, and that there may be as 
many as six generations of this insect annually in the latitude of the 
District of Columbia. During the warmest summer months the life 
cycle requires but twenty-four days; in early spring, from six to ten 
weeks. At Washington the species winters over, in the adult state, 
even in a well-warmed indoor atmosphere. 
The mature beetles will feed upon sugar, and have been reported in 
starch, tobacco, and dried meats, but it is doubtful if the insect will 
breed in such substances. The beetles or their larve have a bad habit 
of perforating the paper bags in which flour and other comestibles are 
kept. When present in boxes of fruit there may be no visible evidence 
of their presence until the bottom is reached, but here they will be 
found in great numbers and when disturbed scamper off in great haste. 
This insect is almost invariably present wherever the Indian-meal 

