REPORT OF THE ENTOMOLOGIST. 15 
The Colorade or western potato-bug, Doryphora 10-lineata, (Agri- 
cultural Report, 1867, page 63,) is still traveling rapidly eastward. The 
first notice of this insect was in the Prairie Farmer, August 29, 1861, 
and it is said to have made its appearance in the far West, and to have 
traveled east about three hundred and sixty miles in six years, or sixty 
miles a year. It feeds on the potato, tomato, egg-plant, horse-nettle, 
Datura Wrightii, Jamestown weed, ground cherry, &c. According to 
Professor Verrill’s excellent description of the habits, &c., of this insect, 
the eggs, to the number of 1,000 to 1,200, or even more, are deposited 
by the female on the young leaves of the potato; these eggs are attached 
by one end to the under node of the leaves, usually in clusters of one to 
two dozen. The larve hatch in a few days; there are several broods 
annually, and the last brood passes the winter as pup under the earth. 
The pupe are formed under ground, and remain, during the summer, as 
pupe from ten to twelve days. The insects, after laying their eggs, do 
not die, as most insects do, but appear to live a long time, Professor 
Daniels, of the Wisconsin University, having kept a female alive six 
weeks after she had laid 1,200 eggs. Professor Verrill recommends Paris 
green, mixed with eight to twelve parts of wheat-flour or with eight 
parts of wood-ashes, dusted over the insects when the plants are wet 
with dew. He, however, very prudently adds: “It may be questioned 
whether it is safe or advisable to mix dangerous mineral poisons with 
the soil, for the arsenic and copper will remain in the earth, and may be 
absorbed by growing vegetables, or cause mischief in other ways.” It 
is also stated in the American Entomologist that Paris green (arsenite 
of copper) is a slow but dangerous poison, and when dusting plants with 
it the greatest care should be taken that the wind may not earry it 
toward the person of the operator. It may even injure the soil if used 
repeatedly. Small doses of arsenie have rather promoted the growth of 
rye, but arsenite of copper is much more virulent in its effects, and other 
_ crops may be essentially injured by it. A very thin dusting with Paris 
green, mixed with flour to reduce its strength, will kill the insects, but 
if used too freely it becomes injurious to vegetation. Professor A. J. 
Cook, of the Michigan Agricultural College, says: “Some of our potato 
vines and ege-plants have been totally ruined by a too free use of this 
poison ;” and adds, ‘We use one part of mineral to five parts of flour.” 
To ascertain whether the plants would readily take up the arsenic suffi- 
ciently to become hurtful, an experiment was made in the Department by 
planting some healthy peas in two flower-pots, one containing merely com- 
mon earth, and the otber earth mixed with a quantity of Paris green. The 
peas in the first flower-pot germinated and grew finely, while those iu 
the Paris green did not even sprout, but rotted in the ground. A few 
well-sprouted peas were then taken from the healthy pot, and placed in 
the fower-pot containing the arsenite of copper. Tbe next morning all 
the peas were found dead, proving that if Paris green be used too freely 
the soi] is thereby injured and reudered unfit for culture. This dan- 
gerous remedy has been used already to such an extent that it is stated 
12,000 pounds were sold in one season at La Crosse, Wisconsin, for the 
destruction of these insects. 
The Colorado potato-bug is now reported in Minnesota, Wisconsin, 
Michigan, Indiana, aud Ohio. On the northern side it is said to have 
reached Canada. It is held that these insects possess poisouous quali- 
ties when handled, and many instances are reported of injuries produced 
by gathering or crushing them in the naked hand. 
There is another beetie which very much resembles the true Colo- 
rado potato-beetle, the Doryphora juncta, (Germar.) It has been 
