576 
THE STUDY OF INSECTS. 
paragus bearing the eggs of this beetle, also a beetle and a 
larva enlarged. The beetle measures about a quarter of an 
inch in length. Where this pest occurs 
care should be taken to destroy all wild 
asparagus. This will force the beetles to 
lay their eggs upon the shoots that are 
cut for market. The larvse hatching 
from such eggs will not have a chance 
to mature. 
The Colorado Potato-beetle, Do¬ 
ry phor a dccemlineata (Do-ryph'o-ra dec- 
em-lin-e-a'ta).—A good many insect 
tramps have come to us from Europe 
and from Australia, and appropriated 
whatever pleased them of our grow¬ 
ing crops or stored grain. But two of 
our worst insect pests have swarmed 
out on us in hordes from their strongholds in the 
region of the Rocky Mountains. These are the Rocky 
Mountain Locust and the Colorado Potato-beetle 
(Fig. 702). The latter insect dwelt near the base 
of the Rocky Mountains, feeding upon the sand- 
burr (Solatium rostratum ), until about the year 
1859. At this time it began to be a pest in the 
potato-fields of the settlers in that region. Having acquired 
the habit of feeding upon the cultivated potato, it began its 
eastward march across the continent, spreading from potato 
patch to potato patch. At first the migration took place at 
about the rate of fifty miles a year, but later it was more 
rapid; and in 1874 the insect reached the Atlantic 
coast. 
The Three - spotted Doryphora, Doryphora 
clivicollis (D. cliv-i-col'lis).—This resembles the 
Colorado potato-beetle in size and form. It is 
of a deep-blue color, except the wing-covers, which are 
orange, with three dark-blue spots on each (Fig. 703). 
Fig. 702. 
Fig. 703. 
