Mr. P. Walker's Descriptions of Aphides. 339 



4th variety. Bright yellow, having a brown line along the head 

 and the chest, and a line of the same colour on each side of the 

 latter, which has also a small brown spot at its tip : there are 

 four rows of brown spots on the abdomen : the tips of the shanks 

 are brown. 



During the summer it has many other tints of yellow and of 

 green, more or less varied with brown and black. During the 

 spring of 1846 I found it in abundance feeding on the dwarf 

 chestnut (Castanea purnila), a native of America, but with this 

 exception the oak seems to be its only support. 



There are two other varieties of A. Quercus : in the first the 

 body is rather short and nearly linear, and the head is as broad 

 as the chest ; in the second the body is longer, and increasing in 

 breadth from the head till near the tip of the abdomen, and the 

 head is narrower than the chest. 



The oviparous wingless female. Its season is from the middle 

 of October to the end of November : the variableness of its colour 

 is partly owing to the orange eggs which it incloses : it is often 

 bright yellow and has a lively green stripe on each side of the 

 body : the abdomen is not a little lengthened behind : the feelers 

 are pale yellow ; the tips of the joints are black : the legs are 

 pale yellow ; the hind-shanks sometimes and especially towards 

 the base are slightly dilated, and of a rather darker colour than 

 the other shanks. 



1st variety. Yellowish green. 



2nd variety. Pale orange. 



3rd variety. Brilliant orange with a pale yellow or pale green 

 head. It has also various tints of green and of yellow. 



The body slightly increases in breadth from the head till near 

 the tip of the abdomen : the feelers are much shorter than the 

 body : the front of the head is beset with bristles : the sides of 

 the fore-chest are not notched : the legs are rather short. 



The winged male. It appears in the autumn, and pairs with 

 the oviparous wingless female in October : it is grass-green : the . 

 disc of the chest is black, and there is a broad black line along 

 the disc of the abdomen : the feelers and the eyes are black, and 

 the former are longer than the body ; the fourth joint is much 

 shorter than the third ; the fifth is shorter than the fourth ; the 

 sixth is much shorter than the fifth ; the seventh is a little longer 

 than the sixth : the legs are pale yellow ; the thighs are pale 

 green, and with the exception of the fore-thighs they are shaded 

 with black. 



1st variety. Buff : the abdomen is dull buff marked with black, 

 and has a row of black spots on each side : the nectaries are also 

 black. 



The wing-veins are much more strongly marked than those of 



23* 



