ROSEBREAST VS. POTATO BEETLE. 47 
There remains for consideration the family of beetles which con- 
tributes most largely to the grosbeak’s subsistence, namely, the leaf- 
beetles (Chrysomelide). This family, as an item of food of the 
rosebreast, is not only most important among beetles, but is only 
second among both animal and vegetable items. In it are included 
a number of pests preyed upon by the bird, such as the striped and 
spotted cucumber beetles, the strawberry rootworm, the plum leaf- 
beetle, the locust leaf-miner, and in addition that pest which figures 
so largely in any discussion of the economic value of the roge-breasted 
grosbeak, the notorious Colorado potato beetle (fig. 25). 
The original home of this insect was in Mexico and the Rocky 
Mountains, where it fed upon the sand-bur (Solanum rostratum), 
a plant closely related to the potato. Finding a new and abundant 
supply of food in the cultivated potato, the beetle immediately began 
to multiply and to migrate eastward, spreading from 1850 to 1874 
over the northern half of the eastern United States. As it encount- 
ered practically no enemies in its new home it became so abundant and 
inflicted so great damage that successful cultivation of potatoes seemed 
no longer _ possible. 
However, just as the 
beetle found a new 
food, so it in. turn be- 
came new food to a 
number of mammals, 
birds, and insects, and 
presently the farmers Fic. 25.—Potato beetle (Leptinotursa decemlineata). 
learned to destroy it (From Chittenden, Bureau of Entomology.) 
inlarge numbers with poisons. Hence it is no longer greatly 
dreaded, though in most sections constant vigilance must be exercised 
to prevent it from ruining the crop. 
Naturally during the period when the beetle was doing most dam- 
age everyone was on the lookout for means of checking its increase, 
and the discovery of each new natural enemy was heralded far and 
wide. Attracting most notice among these was the rose-breasted gros- 
beak, and many articles were written calling attention to the newly 
discovered trait of this beautiful bird. It should be noted also that 
several other birds, including the bobwhite, prairie chicken, sharp- 
tailed and ruffed grouse, red-tailed hawk, nighthawk, cuckoo, crow, 
English sparrow, cardinal, scarlet tanager, wood, hermit, and olive- 
backed thrushes, and robin, eat potato beetles occasionally. 
The grosbeak’s habit of feeding on the potato beetle was noted 
almost simultaneously in many localities, and references are at hand 
for the States of Missouri, Iowa, Minnesota, Wisconsin, Illinois, 
Michigan, and Ohio. The rosebreast actually exterminated the po- 
18848—Bull. 32--08——1 ‘ 
