bronzed reflection on the dorsum, the under side being generally paler and covered 

 with a more or lers distinct pruinous secretion. Otherwise they are like the spring 

 migrants. 



Sexual female. — The mature sexual females (fig. 1, b and/) measure from 1.6 to 1.8 mm 

 in length; they are oval and almost equally tapering toward each end. The antennae 

 are short, about half the length of the body, and five-jointed, the spur being the 

 longest, with the third joint somewhat shorter; all of the joints are plain. The 

 nectaries are short, and do not reach to the end of the body; they arc usually taper- 

 ing, cylindrical, or rarely slightly clavate; the tail is still shorter, its basal half 

 rather broad, with the sides parallel, while the terminal part is broadly triangular 

 and covered with minute sharp points. The posterior tibiae are more or less dis- 

 tinctly inflated and provided with numerous circular, sensorial pores. The color of 

 these sexual females varies more or less; some are of a pale, dirty orange, marked 

 with irregular dusky spots, while others are still darker, spotted only along the 

 sides; many are entirely of a greenish dusky color, often exhibiting in front of the 

 nectaries a lateral row of small, oval, whitish spots; all are, however, provided with 

 a reddish shading around the base of the nectaries. The eyes are brown, the anten- 

 na?, legs, and tail dusky and the nectaries black. Each of them contains from two 

 to four or five eggs. These females, either before or after copulation, forsake their 

 position on the leaves or branches and commence to travel restlessly about, in order 

 to select a secure spot for depositing their eggs, when, especially during warm days 

 of October, every part of a tree may be seen covered with them, either in copula or 

 engaged in depositing their eggs. 



Male. — The males (fig. 1, d and e) as a rule are generally smaller than the migratory 

 females; their expanse of wings ranges between 5.4 to 7 mm and the length of their 

 body between 1.2 to 2 mm . The general appearance of the male is very similar to that 

 of the migratory female, though the abdomen is narrower and the last two segments 

 more j^rotruding. The general color ol the abdomen is either orange or greenish 

 yellow, though frequently there is a more or less defined, dusky, median line, ter- 

 minating, between the nectaries, in a dusky spot. The antennae are generally 

 somewhat longer and stouter than in the migratory female; joints three and four 

 more strongly and more densely tuberculated and the spur longer than joint three. 

 The genital armature consists of two elongated, triangular lobes or claspers, rounded 

 at the end and covered with erect hairs, between which projects a cylindrical sheath, 

 containing the colorless and flexible organ, which frequently may be observed 

 extruding in a hook-like fashion. 



Before maturity of the females the males rest motionless on the under side of the 

 leaves from which they draw their nourishment, though no sooner have the females 

 cast their last skin than they become very nervous and restless and walk briskly 

 about on the branches and the trunk on which the females have congregated, so that 

 frequently thousands of both sexes maybe observed, among them many in copula, 

 and often several males may be seen paying attention to the same female. 



All of those destined to produce a sexual generation the following fall remain and 

 multiply on grains and grasses, though producing at certain times a migratory form 

 to enable them to spread and to protect themselves against destruction over a large 

 area of the country, during which time for a greater or less extent certain external 

 changes take place, the extreme forms of which may easily pass as distinct species, 

 when toward the second fall they return again to the original form. 



NATURAL ENEMIES AND PARASITES. 



Fitch, in his admirable work on the apple louse, refers to the larvae 

 of various aphis lions (Chiysopa) and ladybirds (Coccinellida 1 ) as 

 being very effective in keeping the aphides in check, whereas in con- 



