PRACTICAL PAPERS—COLORADO POTATO BUG. 333 
egg-plant, the horse-nettle, and the potato, all three of them 
belong to the same genus ( Solarium ,) as the wild plant upon 
which the larvae originally fed in the Rocky Mountain region ; 
but the egg-plant and the horse-nettle are botanically more 
closely related to the last than is the potato; being, like the 
Rocky Mountain potato, covered with thorny prickles, while 
the cultivated potato is perfectly smooth. On the other haud, 
the cultivated potato is much more nearly related to the Rocky 
Mountain species than is the tomato ; which last has, by mod¬ 
ern botanists, been removed from the genus to which the other 
two appertain, and placed in a genus by itself. It would, seem, 
therefore, that the closer a plant comes to the natural food- 
plant of the insect, the better the insect likes it. 
It is undoubtedly a most singular and note-worthy fact that, 
out of two such very closely allied species as the bogus and 
true Colorado potato bugs, feeding respectively in the first in¬ 
stance upon very closely allied species of wild potato Solarium 
rostratum and S. Carolinense ,) the former should have pertinaci¬ 
ously refused, for about half a century, to acquire a taste for 
the cultivated potato, with which it was all the time 
in the closest and most immediate contact, while the latter ac¬ 
quired that taste as soon as ever it was brought into contact 
with the plant. But, after all, this is not so anomalous 
and inexplicable as the fact that the apple-maggot fly (Trydeta 
pomonella ), Walsh,) which exists both in Illinois, New York, 
and New England, and the larvae of which feeds in Illinois up¬ 
on the native haws, and has never once been noticed to attack 
the imported apple there, should, within the. last five years, 
have suddenly fallen upon the apple, both in New York and 
New England, and in many localities there have become a more 
grievous foe to that fruit than even the imported apple-worm. 
(Carpocapsa pomonella , Linn.) Thinking that it might be pos¬ 
sible that, although the bogus Colorado potato bug has for 
about a half century refused to feed upon the potato in a 
state of nature, it might be compelled by starvation to feed up¬ 
on that plant in a state of confinement, we placed two of the 
