258 Mr. F. Walker's Descriptiom oj Aphides. 



in the winged insect. The young ones in the pupa or in the 

 winged insect sometimes exceed thirty in number, but are then 

 of various sizes ; sometimes they are of large size and only four 

 in number. It is devoured by the grubs of CocdnelUB, Hemerobii, 

 ChrysopcB and Syrphi. 



The oviparous wingless female. Appears in the autumn and 

 lays its eggs during the latter part of October and in the be- 

 ginning of November, when it sits on the leafless bough. It is 

 brown with black bands : the feelers are black and shorter than 

 the body : the mouth is dull yellow ; its tip and the nectaries are 

 black : the eyes are dark red : the legs are yellowish brown : the 

 hind part of the body is lengthened like that of A. Platanoidis. 



1st variety. Green. 



2nd variety. Dusky yellow, or dull reddish yellow : every seg- 

 ment has a brown line across the disc, and another along each 

 side border : the legs are dull yellow ; the knees are brown ; the 

 feet and the tips of the shanks are black. 



The winged male. It pairs vrith the wingless female at the end 

 of September : it is darker than the winged female, and like it is 

 sometimes covered with a white bloom : the head and the chest 

 are mostly black, and there is a compact row of large black spots 

 along the abdomen : the feelers are longer than the body : the 

 mouth is short, and reaches a little beyond the hind-border of 

 the fore-chest. 



Length of the body If — 2^ lines ; of the wings 4 — 5^ lines. 



4. Aphis comes. 



This insect is of rare occurrence, and has much resemblance to 

 Aphis Betula. 



The viviparous winged female. Found on the birch, Betula 

 alba, in August and in October. The body is yellowish brown, 

 and rather long : the front of the head is rather narrow and 

 nearly straight, and there is a slight protuberance at the inner 

 base of each feeler : the feelers are black, setaceous, slightly 

 hairy, and much shorter than the body ; the first and the second 

 joints are yellowish ; the fourth is much shorter than the third ; 

 the fifth is much shorter than the fourth ; the sixth is not half the 

 length of the fifth -, the seventh is a little shorter than the sixth : 

 the mouth is yellow, and reaches to the middle hips ; its tip is 

 black : the eyes are dark red : the disc of the chest and that of 

 the breast are black : the abdomen has two black spots on each 

 side : the nectaries are extremely short, and like those of A. Be- 

 tulce : the legs are brownish yellow, long, and somewhat hairy ; 

 the feet, the knees, and the tips of the shanks of the fore-legs and 

 of the middle legs, and the whole of the hind legs excepting the 

 base of the thighs, are black : the wings are colourless ; the >\ang- 



