1296 The Zoologist— July, 1808. 



Notes on Aphides. By Francis Walker, Esq., F.L.S. 



(Continued from S. S. 1123.) 



Genus 7. Aphis, Linn. 



Front flat or convex. Antennas not seated on a frontal tubercle, 

 smooth, generally shorter than the body ; seventh joint longer than the 

 sixth, or at least as long. Nectaries cylindrical or attenuated from 

 the base, rarely very small, very rarely none. Tail more or less 

 prominent, sometimes none. Cubital vein of the fore wings twice- 

 forked. 



Typical species, A. Sambuci, Linn. 



A. Tail more or less conspicuous. 

 A. Nectaries longer than the tail. 



a. Body green, or luteous-green, or olive, or ochraceous or lemon-colour, 

 sometimes very pale. 

 a. Body powdered. 



* Nectaries surrounded by rust-colour at the base. 



f Nectaries cylindrical, lutescent, black at the tips. . .1. Padi. 



f+ Nectaries black ; tips paler, attenuated. . . 2. Cratagi. 



** Nectaries not surrounded with rust-colour at the base. 



f Abdomen green-gray, with dorsal transversely arranged and with 



marginal black points. . . . .3. Brassica. 



ff Abdomen green or greenish brown, with no dorsal points, at least 

 in the apterous form. 

 % Antennae half tbe length of the body. Nectaries black. 4. Avencc. 

 XX Antenna; as long as the body. Nectaries green in the apterous 



form, black in the winged form. . . 5. Lacluca. 



a. Body not powdered. 



* Nectaries green or whitish, or lutescent; the extreme tips sometimes 



black or brown, 

 f Tail as long as half the length of tbe nectaries or longer. 

 } Abdomen green. 

 § Dorsum dull, of one colour. . . .6. Naslurlii. 



§§ Dorsum varied with brown. ... 7. Vlinopodii. 



XI Abdomen luteous-green, sometimes marked above with longi- 

 tudinal green lines. 

 § Body broadly oval, obtuse behind. Antennae half tbe length 



of the body. ..... 8. Malva. 



§§ Body oblong oval, acute behind. Antenna nearly as long 



as the body. .... 9. Eupatorii. 



ft Tail shorter than half the length of tbe nectaries. 

 X Nectaries extending beyond tbe tip of the abdomen. 



§ Nectaries long, very pale. Tail brownish green. 10. Saliceti. 



§§ Nectaries moderately long, like the tail in colour. 1 1 . Urticce. 



