Beetles 
289 
The darkling-beetles constitute a large family, more than four hundred species 
being known in this country, although comparatively few of them are at 
all familiar. They are mostly dull or shining black, and feed on dry vege¬ 
table matter, often in a state of decay. Some live in grain, flour, meal, or 
sawdust; others in living or dead fungi, and a few 7 are probably predaceous. 
A common species in mills, stables, grocery-stores, and pantries is the meal¬ 
worm beetle, Tenebrio molitor , J to J inch long, flattened, brownish, with 
squarish prothorax and longitudinally ridged elytra. The stout, cylindrical, 
hard-skinned, waxy, yellowish-brown larvse, or meal-worms, infest flour 
and meal. They are often bred by bird-fanciers as winter food for insect¬ 
eating song-birds. For this purpose they are raised in large numbers in 
warm boxes partly filled with bran, in which they undergo all their metamor¬ 
phosis. T. obscurus is a darker, almost black, species found also in mills 
and granaries. Both of these species have been spread all over the world 
by commerce. A smaller brown species, Echocerus maxillosus , J inch long, 
is common in the southern states in old and neglected flour. 
Uloma impressa, J inch long, deep mahogany-brown, is common in the 
east, occurring in decaying logs and stumps. Smaller species of the same 
genus, lighter in color, are also to be found in 
similar places. An odd-looking species called 
by Comstock the forked fungus-beetle, Boleto- 
therus bijurcus , is not uncommon in the north 
and east in and about the large shelf-fungi 
(Polyporus) that grow on the sides of trees. 
The surface of the body and elytra is very rough, and two conspicuous 
knobbed horns project forward from the pro thorax. The larvae (Fig. 400) 
live in the fungi. 
The other of the two larger heteromerous families, the Meloidae, numbering 
about 200 North American species, includes beetles of unusual structural 
character and appearance, of peculiar physiological properties, and of a 
highly specialized and unique kind of metamorphosis. The Meloids are 
known as oil-beetles from the curious oily fluid emitted by many species 
when disturbed, and as blister-beetles from the inflammatory and blistering 
effect of the application of the pulverized dry body substance to the human 
skin. This powdered blister-beetle is known to pharmacists as cantharides, 
and is a recognized therapeutic substance. The beetles are rather long 
and slender-legged and have a soft fleshy body with flexible wing-covers 
which are sometimes rudimentary, being then short and diverging (Fig. 
401). The head is broad and set on a conspicuous neck, and hangs with 
mouth downward. They are to be found crawling slowly about over field- 
flowers, as goldenrod, buttercups, etc., often in companies of a score or more 
individuals. Many of the species are brightly colored, metallic bronze, 
Fig. 400.—Larva of a Tene- 
brionid, Boletotherus bifurcus. 
(Twice natural size.) 
