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



on each side : the feelers are nearly as long as the body : the 

 mouth is dull yellow ; its tip and the nectaries are black, and the 

 latter are one-tenth of the length of the body. 



The second form of the viviparous wingless female. The winged 

 mother in the beginning of June gives birth to a large progeny 

 of pale green young ones ; these are covered with long white 

 hairs, and have white limbs and brown eyes ; they sit in clusters 

 beneath the sycamore leaves ; the number in each group varies 

 from ten to some hundreds, and they continue thus without any 

 increase of size for three months or longer ; they are arranged 

 with their heads converging towards the centre of the group. There 

 is a thin membrane or rim or edge round the body : the eyes are 

 red : the mouth reaches a little beyond the hind-hips ; its tip is 

 brown : the feelers are more than half the length of the body : 

 the legs are rather short and stout. In September an alteration 

 takes place ; the body increases in size, becomes more and more 

 plump, and much less hairy, and its rim ceases : the fourth joint 

 of the feelers is about half the length of the third ; the fifth is as 

 long as the fourth ; the sixth is much shorter than the fifth ; the 

 seventh is rather more than twice the length of the sixth. I have 

 found the full-grown viviparous wingless female on the maple in 

 August, but its occurrence then and during the preceding month 

 is uncommon : the body is rather narrow, but rapidly increases 

 in breadth towards the hinder part : the back and the limbs are 

 hairy, and the feelers are nearly as long as the body j the fourth 

 joint is much shorter than the third ; the fifth is very nearly as 

 long as the fourth ; the sixth is not half the length of the fifth ; 

 the seventh is longer than the fifth. Both the wingless and the 

 winged viviparous females in October resemble those of the pre- 

 ceding generations : the forehead is slightly convex, rather bristly, 

 and has no tubercles at the base of the feelers : in the winged 

 insect the seventh joint of the feelers is longer than the fifth : 

 the third wing-vein sometimes sends forth its second fork before 

 two-thirds of its length. 



The oviparous wingless female. This appears in the autumn, 

 and when very young is pale yellow; it acquires its full size 

 during October, and at an early period of the growth two deep 

 green spots appear on the back, and afterwards there are two 

 brown stripes along the back, having a buff" space between them, 

 and sending forth on each side a short branch to the border of 

 the abdomen which is much broader than the chest ; these stripes 

 are sometimes very uneven, or broken, or various in shade and 

 in tint ; the colour of the whole body is also variable, being yel- 

 low, or brown, or green varied with black, or almost black : it 

 contains eight large full-grown eggs which quite fill the body even 

 to the fore-chest : the abdomen is lengthened or drawn out towards 



