and under scales of the bark. The eg-gs are quite small, but may be 

 readih' detected with the unaided eye. These hatch in spring, about 

 the time the young leaves of the apple are pushing out, and the small, 

 greenish "lice," often occurring in large numbers, at once attack 

 these parts. These insects, when fulh^ grown, are the stem-mothers, 

 and soon begin the production of living j^oung, most of which develop 

 into the winged agamic form which migrates to other trees and to other 

 localities, where new colonies are started, the progeny of the third 

 generation also being winged and wingless. In all, some five genera- 

 tions of aphides develop on the apple, but by early July in the lati- 

 tude of ^^'ashington the trees are free from them, and 

 the aphides have become established on grains and '.,><^ 



grasses or other host plants. Upon the approach of 

 fall, apple trees are again infested by the return mi- 

 grants from the grasses and grains, the true females 

 are soon produced, and the winged males come from the 

 grasses upon which the}- have developed. "Winter eggs 

 are deposited during September, October, and early 

 November in the manner indicated. 



THE APPLE APHIS. 



Fig. 3.— Eggs of the 



{AjtJiis mall Fab.) 



In general appearance the apple aphis (tig. 4), or apple 

 leaf-aphis, is nmch like the preceding, with which it has 

 been confused. The body is pear-shaped, instead of oval 

 as in S. avena?^ the colors of both being yellowish green, 

 greenish, or darker, varying considerably in detailed 

 markings and in the several generations. 



Aphis iiKili Fab. {jtomi De Geer) is of European 

 origin, and has only recently made its appearance in 

 this country, Mr. Pergande having first seen specimens 

 collected in the United States in 1897. However, at 

 the present time it is widely distributed, having ])een apple aphis(.4p/((;i 

 recorded from New Jersev, Delaware, New York, Con- "::"'\ «" '^"*^- 

 necticut, Colorado, Michigan, Alabama, and Georgia. 

 The records of this Bureau show it to occur in Kentucky, Louisiana, 

 Oregon, Pennsj^lvania, Nebraska, and Arkansas. In this countr}- the 

 insect appears to infest apple (fig. 1) principally, if not entirely, 

 though in Europe it infests in addition the wild crab {Pyrus nialus)^ 

 pear, and white thorn {Crativgus <>.ryaeavtJui). 



NATUR.\L HISTORY A.ND HABITS. 



The apple aphis has been studied by Dr. J. B. Smith and Prof. E. D. 

 Sanderson. Winter eggs (fig. 3) are deposited by the sexual females 



[Cir.Sl] 



