bb. Cubital 'vein twice forked.— (2) Lachnin^e. 
aa. Winged form unknown.— (4) Rhizobix^e.. 
AAA. Antennae five or only three-jointed. 
a. Winged form unknown.— (5) Tycijeesle. 
aa. Winged form obvious, or at least known. — (6) Chermesixae 
• Sub-family I. Apiiidix^e—G enera. 
A. Antennae on frontal tubercles. 
a. Antennae closely approximate at base front groved. Si- 
phonophora. 
aa. Antenme remote at base, front flat or convex. 
b. First joint of the antennae with a tooth on the inside. Pho- 
rodon. 
bb. First joint of the antennae not toothed. 
c. Nectaries or honey tubes distinctly clavate. Rhopalosiphum. 
cc. Nectaries cylindrical, sometimes hardly attenuated at the base, 
more often incrassated. 
d. Cubital vein twice forked. 
e. Tail much shorter than the nectaries. Myzus. 
ee. Tail longer than the nectaries, rarely equal to them in length. 
Ilyalopterus. 
dd. Cubital vein once forked. Toxoptera 
AA. Antennae not on frontal tubercles. 
a. The seventh joint of the antennae as long or longer than the 
sixth.. 
b. Antennae smooth. 
c. Nectaries longer than thick, or if shorter, or none, then the 
wingless female has a smooth back. 
d. Nectaries cylindrical (very rarely none.) Aphis, 
dd. Nectaries clavate. Siphocoryne. 
cc. Nectaries shorter than thick, or if a little longer, then the fe¬ 
male has a hairy back. MyzocaUis. 
bb. Antennae pilose. 
e. Nectaries cylindrical, or at least twice longer than thick. Cla- 
dobius. 
ee. Nectaries tubercle shaped, much shorter than thick, sometimes 
almost on a level with the surface. Chaitophorus. 
aa. The seventh joint of the antennae as long or longer than the 
sixth. 
f. Species aerial; winged form elegant. Pteroealhs. 
Jf. Species subterranean, winged form unknown. 
g. The third joint of the antennae longer than the fourth; hind 
tarsi one-jointed. Trama. 
gg. Third joint of the antennae as long as the fourth; hind tarsi 
two-jointed. Paracletus. 
Sub-family II. Lachxixae. 
A. Sixth joint of the antennae setaceous. Alpha. 
AA. Sixth joint of the antennae filiform or clavaie, often ending in 
a spur, like a rudimentary joint. 
