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 are probably predaceous. 

 A common species in mills, stables, grocery-stores, and pantries is the meal- 

 worm beetle, Tenebrio molitor, ^ to f inch long, flattened, brownish, with 

 squarish prothorax and longitudinally ridged elytra. The stout, cylindrical, 

 hard-skinned, waxy, yellowish-brown larvae, 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, % inch long, 

 is common in the southern states in old and neglected flour. 



Uloma impressa, \ 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 Com stock the forked fungus-beetle, Boleto- 

 therus bifurcus, is not uncommon in the north FIG. 400. Larva of a Tene- 

 and east in and about the large shelf-fungi brionid, Boktotherus bifurcus. 

 /r> i \ *u , *u j r * (Twice natural size.) 



(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 prothorax. 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, 



