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



an organ of the same system sending inwards and incHned a little 

 down a similar tube. The summit of the nectary is contracted 

 and then expanded again in a sort of lip, thus acting as a sphinc- 

 ter.^' The legs are pale green, long and slender ; the fore-thighs 

 are stout, and each has a small obtuse tooth on the inner side of 

 its tip ; the knees, the feet, and the tips of the shanks are brown ; 

 the shanks are hairy, longer and more slender than the thighs ; 

 the feet have two joints ; the first is very short, the second is 

 longer and furnished with claws : the wings are colourless and 

 much longer than the body ; the wing-ribs and the wing-brands 

 are green ; the veins are brown, and their tips are slightly clouded : 

 the fore-wing has a strong rib-vein running parallel to and a little 

 below its fore-border ; four branch-veins spring from it ; the first 

 and the second pass to the hind-border of the wing ; the third is 

 divided at about one-third of its length ; one branch joins the hind 

 border, the other is again forked, and the upper part of the fork 

 runs to the tip of the wing ; the fourth or radial vein is short and 

 curves upwards : the lower wing has a rib-vein that runs very 

 near the fore-border, and sends forth two simple veins to the 

 hind-border. 



1st vai'iety. The lobes of the middle chest and the disc of the 

 breast are black. 2nd var. With a row of transverse black spots 

 along the back of the abdomen : the legs are pale yellow ; the 

 knees, the feet, and the tips of the shanks are black : the wing- 

 ribs and the rib-veins are yellow. 3rd var. The disc of the head, 

 two spots on the fore-chest, and the middle chest are black : the 

 feelers are black and covered with a white bloom ; their base is 

 dull yellow. 4th var. The body is tinged with bright red. In 

 the 5th var. the disc of the head and the middle chest are green, 

 in the 6th they are buff, in the 7th they ai'e red, in the 8th they 

 are lilac. 9th var. The body is deep black ; the head is tawny. 

 10th var. The whole body is covered with a white bloom. 11th 

 var. The body is pale red, or rust-colour : the back of the abdo- 

 men is traversed by a row of short black bands : this variety 

 occurs chiefly in the autumn. 12th var. The wing-brand is 

 colourless. 



Sometimes one hundred of these insects may be seen under a 

 single leaf, and innumerable swarms hover about the sycamore- 

 trees during the fine calm autumn evenings. In this season it 

 still continues to bring forth young ones, which the fall of the 

 leaf soon carries away to the earth, where they perish. When 

 it abounds, a great variety of insects, especially of Hymenopterous 

 and of Dipterous flies, come to feed on its honey-dew ; this matter 

 stops the pores and hastens the decay of the leaf, which towards 

 the end of autumn is often covered with little Acari, the devourers 

 of the dead Aphides. This honey falling on the upper surface of 



