STATE HORTICULTURAL SOCIETY. 151 



Mercer county, Illinois; two-thirds of all the specimens he gathered at the 

 time belonging to this species. I have noticed the same species in the 

 southern portion of the State, and am inclined to think a close and care- 

 ful examination of the Aphides infesting the leaves and twigs of our apple 

 trees would possibly reveal the fact that this species is as common and as 

 numerous as the A. »ia/i, or, as Dr. Fitch believes, more numerous. The 

 natne given implies that it is confined to the leaf, but this, I think, is a 

 mistake ; that this is the habit of the species, I think quite probable, and 

 corresponds with my observations, of which, unfortunately, I have no 

 notes, but I certainly have noticed the winged specimens, and if I recol- 

 lect rightly, apterous individuals also, on the tender twigs. 



15. Aj>/i/s cerasi, Fabr. The Cherry-tree Plant-louse. 



This is another introduced species of this numerous family, and, like 

 most of the European or Eastern insectsAvhich have been introduced into 

 this country, appears to thrive equally well, if not better, than its con- 

 geners, as it is in some sections the most common and abundant species. 

 Goureau describes the species found in France as averaging a little less 

 than one-tenth (0.08) of an inch in length ; body, black ; antennee, black, 

 with the middle portion yellowish; abdomen, black; legs, black; the 

 tibi;.Te, pale yellowish ; wings, pellucid. Found on tlie under side of the 

 cherry tree, which they roll and crisp. 



As seen in this country, the wingless females measure about five or 

 six hundredths of an inch in length, the winged individuals measuring to 

 the tips of the closed wings rather over one-tenth of an inch. The winged 

 female is of a shining black color, the abdomen nearly twice as broad as 

 the thorax, giving it an ovoid or egg-shape, with the smaller end in front, 

 which is more clearly shown in the wingless individuals; antennae, black, 

 about three-fourths the length of the body ; the beak, short, black or dusky ; 

 legs, black, except the basal half of the thighs and the basal portion of the 

 tibise, which are pale or whitish ; wings, pellucid ; the base, outer margin 

 and rib-vein, white; remaining veins usually dusky; the second vein is 

 about a third farther from the first at its tip than at its base ; third slightly 

 farther from the second at tip than base. 



The wingless females agree very nearly with the above, so far as relates 

 to the body. The antennae are whitish, except the two basal joints and 

 apical half ; beak, whitish, with the tip only black; legs, white; feet, tips 

 of tibise and tips of thighs, black. The abdomen has an elevated lateral 

 margin. 



The young larvae are at first dull white or pale yellow, but grow 

 darker as they increase in age. 



This infests the leaves of the cultivated or garden cherry tree {Cera- 

 sus vulgaris), to the varieties of which it appears to be exclusively con- 

 fined. They hatch out in the spring, as soon as the leaves commence to 

 unfold. There are a number of broods produced in the same manner, 

 and similar in habits to the other species of the genus; although the sum- 

 mer broods appear to be exclusively females, among them we very often 

 find winged individuals. They often become very numerous, covering 



