452 Mr. F. Walker’s Descriptions of Aphides. 
lar, Populus dilatata, and of the willow-tree, Salix alba, vitellina 
and caprea ; it is fixed there in dense masses, and each row over- 
laps the one below it. Large companies of ants [Formica rufa) 
are continually passing up and down the trunks of the trees 
whereon it is stationed. The body is oval, rather flat, hairy, and 
of a very dull yellow colour, and thickly covered with gray pow- 
der : the front is broad and slightly convex : the feelers are seta- 
ceous, hairy, and much less than half the length of the body ; 
their tips are dark brown ; the fourth joint is less than half the 
length of the third ; the fifth is full as long as the fourth ; the 
sixth is little more than half the length of the fifth ; the seventh 
is much longer and more slender than the sixth : the mouth 
reaches the hind hips ; its tip is dark brown : there are six rows 
of dark spots along the back : the nectaries are yellow, and not 
more than one-twentieth of the length of the body : the legs are 
stout and rather hairy ; the fore-legs are much shorter than the 
hind-legs ; the feet, and the tips of the shanks and of the hind- 
thighs are dark brown : the body contains about twenty young 
ones of various size. 
The viviparous winged female. This has much resemblance to 
the viviparous wingless female : the sixth joint of the feelers is 
much less than half the length of the fifth : the discs of the head, 
of the chest, and of the breast are dark : the wings are colourless, 
and of moderate size ; the veins and the brand are tawny ; the 
rib-veins widen into irregularly spindle-shaped brands soon after 
the middle of the fore-border of the wing ; the first branch- vein 
is nearly straight ; the second is slightly curved ; the third is in- 
clined inwards, and forms two angles as usual ; its first fork begins 
after one-third, and the second at two-thirds of its length ; it ap- 
proaches very near its source before it becomes obsolete. 
Length of the body line; of the wings 3 lines. 
It is infested by an Aphidius, and is also devoured by the 
grubs of a Sgrphus and of an Agromijza. 
24. Aphis Salicis. 
Aphis Salicis f Linn. Syst. Nat. ii. 736. 26 ; Faun. Suec. 995 ; 
Gmel. ed. Syst. Nat. i. 2207. 2210; Fabr. Syst. Ins. ii. 389. 46; 
Ent. Syst. iv. 219. 47 ; Syst. Rhyn. 301. 47 ; Reaum. Ins. iii. 
281-350. t. 22. f. 2; Deg. Ins. iii. 50. 11; Schrank, Faun. 
Boic. ii. 1. 102. 1176; Rossi, Faun. Etrusc. 264. 1398; Kalt. 
Mon. Pflan. i. 131. 100; Ratz. Forst. Ins. iii. 218. 18. 
SalicifeXj Amyot, Ann. Soc. Ent. Fr. 2“® serie, v. 480. 
The viviparous wingless female. Dull green, covered with white 
powder, rather flat, and increasing in breadth from the head till 
near the tip of the abdomen : there is a row of black spots on 
each side of the body : the sides are dull orange, and so disposed 
