1910] Key to the Genera of Aphidinae 317 



Gen. Greenidea Schouteden. 



type S. artocarpi Westwood. 



Antennae longer than the body and six segmented; spur of 

 sixth shorter than the third segment; first segment sHghtly 

 gibbous on the inner side. Antennal tubercles large and taper- 

 ing, front of head wide and flat. Body long and slender, wings 

 long, venation variable but usually the cubitus is but once 

 forked. Nectaries almost as long as the body, slender and 

 nearly cyhndrical. Cauda short, broader than long and rounded 

 at the tip; base slightly constricted; anal plate rounded. Body 

 and appendages exceedingly hairy. 



Tribe Macrosiphini 



The author has divided this group from the following in 

 order that the key may not contain too many conflicts. The 

 division is made between species having distinct antennal 

 tubercles and those having none or at the most indistinct 

 tubercles. However should a certain species have distinct 

 antennal tubercles with the other characters w^anting then it 

 would have to go in the next tribe. 



I. Antennal tubercles tapering and very large, not gibbous on the inner side. 



II. 



— Antennal tubercles gibbous or toothed on the inner side ..III. 



1 1 . Nectaries nearly half as long as the body, cylindrical and curved. . . Illinoia. 



— Nectaries at least one fourth the length of the body and vasiform. 



Nectaroaiphon. 



III. Antennal tubercles large, and as long on the outer side as on the inner; 



upper inner angle more or less gibbous. Nectaries variable IV. 



— , Antennal tubercles prominent but not large and the inner side longer than 



the outer or else outer side is but a line VI. 



IV. Nectaries tapering longer than the cauda which is sickle shaped. Wings 



regular with twice forked cubitus Macrosiphixm. 



— Nectaries and cauda variable, wing venation irregular but very striking. 



Veins either wanting or else combined V. 



V. Antennal tubercles with sharp upper inner angle, cauda shorter than the 

 nectaries and tapering. Stigmal and cubital vein almost meet in a broad 

 dark band, giving the wing the appearance of having a closed triangular 

 cell Idiopterus. 



— Antennal tubercles with small round tubercle at upper inner angle. Necta- 



ries tapering and slightly longer than tapering cauda. Wing venation 

 variable but usually with the cubitus once forked, and the hind wing with 



but a single oblique vein Microparsus. 



— • Antennal tubercle with small rounded tubercle at upper inner angle. Nec- 



taries constricted at the middle and tip. Wing venation variable but 

 usually the stigmal and cubital veins are partly joined and form a distinct 



closed cell with four sides Pentalonia. 



VI. Antennal tubercles short but not wedge shaped. Cauda large and long. 



VII. 



— Antennal tubercles wedge shaped with the inner side formed into a tubercle 



or tooth. Cauda short VIII. 



VII. Antennal tubercles slightly gibbous. Antennae much longer than the 

 body, nectaries strongly clavate. Wings with cubitus twice forked. 



Amphorophora 



