286 Beetles 



SECTION TRIMERA. 



Only one family is included in this section of beetles with but three tarsal 

 segments in each foot, namely, the familiar little ladybirds or plant-louse 

 beetles, the Coccinellidae. Their uniformly small size, the semispherical shape, 

 and the "polka-dot" pattern distinguish them readily from all other beetles 

 except perhaps the Chrysomelidie, a few of which are often mistakenly 

 called ladybirds. This is a particularly unfortunate confusion because of 

 the radically different food-habits and consequent economic relation to 

 man of the two families. The Chrysomelida;, or leaf-eaters, both as larvas 

 and adults, attack our croj)s and trees and flowers; the Coccinellidae, or 

 ladyljirds, both as larv;c and adults, feed on plant-lice and scale-in.sects, 

 great enemies of our orchards and gardens, and thus are among our best 

 insect friends. A friend of mine found that his roses were suffering from 

 insect attack; he saw little, convex, black-spotted reddish beetles clamber- 

 ing busily up and down the stems, and he set to work to pick these off one 

 by one and drop into a tin cuj) with petroleum in the bottom. When he had 



d i • I 



Fig. 307. — Some Californian laclyl)ir<l-bL-etles; beginning at left iif upjier row the species 

 are Megilla viligera, Cocciitella ctilijoniica, C. oculnta, llifipndtimiti cunvergens; 

 beginning at left of lower row, Coccindia trijasciala, C. sangiiiiica, C. abdominalis, 

 Megilla maculata. (Twice natural size.) 



a full pint he showed them proudly. But the more little round beetles he 

 picked off the more rapidly wilted his roses. And for the wholly sufficient 

 rea.son that he was collecting and killing the ladybirds that were making 

 a fight — a losing one in the face of my friend's active part in it — against 

 the hosts of tiny inconspicuous green rose-aphids that were sucking the sap 

 out of the rose-stems and buds. So be it remembered that not all bugs 

 are bad bugs, but that some, like the ladybirds, are most effective helpers 

 in waging war against the real pests! 



There are about 150 species of ladybirds known in the United States, 

 and almost all are reddish brown with black dots or black with reddish 



