ENT oO. 87. Issued June 3, 1907. 
aited States Department of Agriculture, 
BUREAU OF ENTOMOLOGY, 
L. O. HOWARD, Entomologist and Chief of Bureau. 
THE COLORADO POTATO BEETLE. 
é 
(Leptinotarsa decemlineata Say.2) 
By F. H. CHITTENDEN, 
Entomologist in Charge of Breeding Experiments. 
There are few more familiar insects to the farmer and others who 
lead a rural life than is the Colorado potato beetle, or “ potato bug,” 
as it is commonly known; and yet scarcely more than forty years 
ago the potato crop of the United States had no very important insect 
enemy. Not many years later this insect had, by its depredations on 
potato, one of our most valuable food staples, caused as great concern 
as have the San Jose scale and cotton boll weevil in the past decade, 
and was also the subject of much study and experiment. Although 
so common an insect, 
many are not thor- 
oughly acquainted 
with its life history 
and habits and with 
the best methods of 
combating it, and this 
apples particularly to 
persons farming in Fis. 1.—Colorado potato beetle (Leptinotarsa dece mlineata): a, 
Beetle; b, larva; c, pupa. Enlarged (original). 
districts only recently 
invaded by the foe. The insect is continually extending its range 
southward, and many complaints are received from localities where 
the pest has not become thoroughly acclimated. 
The potato beetle, notwithstanding all that has been done to 
suppress it, is still a pest of great importance. It is interesting as 
the first known example of an insect native to our Western States 
being introduced eastward and thence practically all over our country 
and Canada (except on the Pacific coast) where potatoes are grown. 
In its early days as a migrant there seemed to have been no check to its 
eastward spread other than natural barriers, such as rivers and lakes 
and the Atlantic Ocean, but in the course of years numbers of nat- 
ural enemies—birds, mammals, and predatory and parasitic insects— 
aFormerly classified and better known as Doryphora 10-lineata-Say. 
30546—No. 87—07 
