ii 



Mr. F. Walker's Descriptions of Aphides. 259 



ribs, the wing-brands and the veins arc tawny ; the fourth branch- 

 vein sends forth its first fork at one-third, and its second fork at 

 two-thirds of its length. The young ones in the body sometimes 

 amount to thirty in number, of which a third part are large and 

 the rest are small. 



1st variety. With four black spots on each side of the abdo- 

 men. 



Length of the body 2 — 2| lines ; of the wings 5 — 6 lines. 



Third Group. 

 The only species in this group differs not from A. comes in 

 structure, but in addition to the three forms before-mentioned it 

 has a fourth, which is the viviparous wingless female. 



5. Aphis ohlonga. 

 Aphis oblonga, Von Heyden, Stet. Ent. Zeit. Jahr. v. 12 ; Kalt. 

 ' Mon. Pflan. i. 144 ; Ratz. Forst. Ins. iii. 219 ; Stet. Ent. Zeit. 

 1844, pp.9, 81, 133,410. 



The viviparous wingless female. The body is brown : the front 



of the head is slightly concave : the feelers are black, setaceous, 



: slightly hairy, and shorter than the body ; the fourth joint is pale 



i yellow at the base, and about half the length of the third ; the 



' fifth is also pale yellow at the base, and a little shorter than the 



; fourth ; the sixth is much shorter than the fifth ; the seventh is 



much shorter than the sixth : the eyes are dark red : the mouth 



is black, yellow towards the base, and reaches to the middle 



hips : the nectaries are shorter than those of A. comes, and do 



: not rise above the surface of the abdomen : the legs are dark yel- 



j low and slightly hairy ; the thighs, excepting the base, the feet, 



1 and the hind shanks, are black. It is the prey of a parasitic grub. 



The viviparous winged female. In colour like the preceding 



i form, but the disc of the chest and that of the breast are black : 



I the wings are colourless ; the wing-ribs, the wing-brands and the 



I veins are tawny ; the second fork of the fourth branch-vein is 



S' ""*her long. 

 Length of the body 1^ line ; of the wings 3 lines. 

 I am indebted to my friend Mr. Haliday for the following trans- 

 lation of an extract from 'Erichson's Bericht,^ &c., 1844: — 



" Ent. Zeitung, pp. 9, 81, 133, 410. Ratzeburg observed a 

 fipecies of Aphis on the birch which continued to produce a living 

 ' progeny, from August into winter, without either male or female 

 appearing. Bouche and Kaltenbach in explanation remark that 

 the males in this family arc not always winged. However, the 

 May following, Ratzeburg, continuing his observations, found 

 the winged females, and afterwards (in October) winged males 

 also which paired with them. The species was then identified as 

 A. oblonga, V. Heyden." 



