THE BEETLE 



73 



shape. They lay their eggs upon the leaves of plants. The 

 larvae feed on the leaves or burrow in the stem. Usuallj' the 

 larva is conspicuously colored and exposed, and relies for i:)rotec- 

 tion upon its disagreeable odor and taste. The most destruc- 

 tive species to agricultm'e in the northern United States is the 

 ten-hned Colorado potato-beetle. Until about 1859 this species 

 fed upon the sand-bur, at the east- 

 ern base of the Rocky iMountains 

 and south into Mexico. With the 

 advent of settlers and the planting 

 of the cultivated potato (a native 

 of Mexico), this more thrifty, 

 cultivated species was adopted as 

 its foodplant, and the jiotato- 

 beetle began its eastern migra- 

 tion. It spread slowly at first, but 

 within fifteen years had reached 

 the Atlantic coast. The little red, yellow, and black asparagus 

 beetle ; the yellow, black-striped cucumber and melon Ijeetle, 

 and the tortoise-l^eetle, whose broa.d, iridescent, translucent 

 eljrtra are consi)icuous on the leaves of the morning-glory, 

 nettle, and other plants, all belong to this family. 



So long has become our list of destructive beetles that it 

 is with satisfaction that we turn at the end to a family which 

 is almost wholly beneficial to the vegetable kingdom as well 

 as to most vegetable-feeders, including man. This is the lady- 

 bird family (Coc'Vinel'lida)^). These beetles hunt their prey 

 both in the larval and adult stages, feeding upon small insects 

 and insect eggs (Figs. 82 and 83). They are especially active 

 in freeing plants from scale-insects and plant-lice. So rapidly 



' From Greek kokkos, kerry. 



Fig. 80. — Orthosoma hrimnenm, 

 the straight-bodied Prionid. 

 Brown color. Nat. size. Photo, 

 by W'. H. C. P. 



