172 



AN ECONOMIC ENTOMOLOGY. 



Fig. 143. 



Rove-beetle and its larva. 



the segments distinctly marked at the edges. These beetles have 

 the sense of smell wonderfully developed, and I have frequently 

 covered a small, freshly-killed animal with a box of wood or 

 tin, only to find next morning a number of the insects beneath 

 it. The species are generally nocturnal, and as scavengers are 

 useful, or at least innoxious. 



The large series of "rove-beetles," or Staphylinid^, is pecu- 

 liar in the short wing-covers, which leave more than half the 

 abdomen exposed. The species are always 

 long and comparatively narrow, usually 

 with a large head and well-developed man- 

 dibles, and live in all sorts of fermenting, 

 ^S decaying, or excrementitious animal or 

 vegetable matter. Most of them are small, 

 and many are found beneath bark, in fer- 

 menting sap, or in fungi, while the larger 

 forms are often found in or under animal 

 excrement, or on or under carrion. In 

 short, the species are scavengers, with a 

 tendency to a predatory habit in some cases, and never any 

 disposition to feed upon growing vegetation. They may thus be 

 accounted either actively beneficial or at least not injurious, and 

 as scavengers they aid in reducing organic matter into condition 

 for assimilation by plant-life. 



The next family meriting attention from its economic interest 

 is the CoccinellidcB, or, as the species are commonly termed, 

 "lady-bugs" or "lady-birds." Scientifically these insects are 

 distinguished by having the tarsi three- jointed only ; but practi- 

 cally they are recognizable by their oval or round form, — always 

 convex, sometimes almost hemispherical, —and by their colors, 

 which are either of some shade of red with black spots and 

 markings, or black, with red or yellow spots. The species are 

 never large, sometimes very small ; but in almost all cases are 

 predaceous, their prey consisting chiefly of plant-lice or scale 

 insects. The larvae, which have the same feeding habits, are 

 usually fusiform, with a small head and quite long legs. They 

 are often prettily colored, sometimes with spiny warts or pro- 

 cesses, and may be seen running about wherever plant-lice 

 abound. Patches of from fifteen to forty of the yellow eggs 



