Mr. F. Walker's Descriptions of Aphides. 333 



it is oval, yellow, rather flat and hairy, and has four rows of 

 black spots on the back, and these spots are often confluent so 

 as to form bands : the feelers are black, and nearly as long as the 

 body, but sometimes they are very much shorter ; the base of 

 each joint is yellow ; the fourth joint is very much shorter than 

 the third, but more than half its length ; the fifth joint is as long 

 as, or a little longer than the fourth ; the sixth is a little shorter 

 than the fifth ; the seventh is more or less shorter than the fifth, 

 and its base does not occupy the whole breadth of the tip of the 

 latter : the fore-chest is broader in proportion to its length and 

 narrower in front than that of the winged female : the abdomen 

 beneath has a shield-like plate on each side near its tip : the hind- 

 shanks are broad; the tips of the fore- thighs and of the middle - 

 thighs, the hind-thighs from the middle to the tips, and the base 

 of the hind-shanks are grayish black : the feet with the excep- 

 tion of the base are black. The eggs which it bears are about six 

 in number. 



1st variety. The abdomen above is nearly black, all its spots 

 being confluent. 



While this oviparous female is employed in laying eggs, the 

 viviparous mother still continues to bring forth young ones which 

 quickly perish by the fall of the leaves where they are seated ; 

 these leaves while fading on the tree are frequented by little 

 white half-transparent Acari. 



The wingless male. It has much resemblance to the wingless 

 female, with which it pairs in September. 



The winged male. This appears in September and October, and 

 then pairs with the wingless female : it is brown : the head and 

 the chest are slightly marked with yellow : the abdomen is yellow, 

 and has a brown border : the feelers are black, and much longer 

 than the body : the legs are yellow ; the hind-thighs, except the 

 base, the base of the hind-shanks, and the tips of the feet, are 

 black ; the knees, and the tips of the shanks are gray : the tips 

 of the wing-veins are less shaded than those of the female usually 

 are, but the colour of the body is darker than in that sex. 



Seventh Group. 



The viviparous wingless females appear in this group, but it 

 is distinguished by the great predominance of the winged female, 

 and is scattered and not clustering on its habitation. The veins 

 of the wings are usually more or less clouded. 



9. Aphis Betulicola, Kaltenbach, Mon. Pflan. i. 44. 

 The viviparous wingless female. This appears in July, but is of 

 rare occurrence ; it is pale orange and oval ; the back is slightly 

 convex and rather hairy : the middle-chest and the hind-chest 



