PLANT LICE. 183 
rather sporadic in their habits. If closely inspected some of 
them are really beautiful objects, with an elongate, slender, more 
or less depressed body, and of a very pale and delicate color. 
The old genus Aplus has been subdivided into many genera, 
which it is not necessary to describe in this report. A consid- 
erable number of very destructive insects belong to this genus, 
and only a few of the more important ones can be discussed. 
Those interested in such matters, and especially in the classifica- 
tion of the Aphidide, should consult the “Synopsis of the 
Aphididz of Minnesota” by O. W. Oestlund, published as bul- 
letin No. 4 of the Geological and Natural History Survey of 
Minnesota. It was published in 1887, hence is somewhat out 
of date, and it is to be hoped that the author will soon give us 
a new edition of this important and necessary work. 
Aphis cerasifolie Fitch. (The Choke-cherry Aphis). 
This is a very common louse, occurring in large numbers 
on the leaves of Prunus virginiana, where it sometimes becomes 
very conspicucus by the deformed leaves on the tip of the branch 
infested by it. The apterous form is thickly covered with a white 
powder, and a large amount of honey-dew is produced, which 
is frequently found in fine liquid drops among the colony of lice. 
The young lice are pea-green, with white feelers, honey-tubes 
and legs. As they grow older a darker green stripe appears 
along the middle of the back. The winged insect is black, with 
a pale green abdomen marked with three dark green dots on each 
side forward of the honey-tubes, and above these a row of im- 
pressed deep green dots extending backwards past the nectaries, 
with a deep green stripe upon the middle of the back, which does 
not reach to the tip. 
Plate XII, Fig. 153, shows a closely related European species, 
the Aphis cerasi Fab. 
Aplus crategifolie Fitch. (The Thorn-leaf Aphis). 
This species is black; abdomen, with a row of blackish dots 
along each side; veins of the fore-wings whitish, black at their 
tips; tibiz or shanks, except at their tips and base of the shanks, 
green; honey-tubes equalling nearly half the distance to the tip 
of the abdomen. Length 0.15 of an inch. (Fitch). 
