A SYNOPSIS OF TEE APHIDIDAE 87 



Tribe Aphidini Wilson 



Wilson, Ann. Ent. Soc. Am., vol., 3, p. 331, 1910. 

 Following is a brief characterization of this tribe, from Wilson: 



The characters which separate this tribe from the previous one [Macrosiphini] 

 are taken as follows: Antennae shorter than the body, or when as long as the 

 body the cornicles and cauda are very short; antennal tubercles, when present, 

 are indistinct, or else the cornicles and cauda are small; when the cornicles are 

 very long or large the development is limited and the other characters are used 

 to place the genera. 



The California genera included by Wilson in this tribe are Aphis, 

 Cerosipha, Coloradoa, Hyalopterus, Liosomaphis, and Siphocoryne 

 [Hyadaphis], In addition to these the author includes Toxoptera 

 because of the small and indistinct antennal tubercles and the short 

 cornicles, and Myzaphis because of the absence of antennal tubercles. 

 The key to the California genera has been formulated by the author, 

 following Wilson, Mordwilko, and Van der Goot. 



1. Antennae five-segmented Cerosipha del Guercio 



Antennae six-segmented 2 



2. Cornicles much shorter than cauda Hyalopterus Koch 



Cornicles about as long as or longer than cauda 3 



3. Cornicles cylindrical, tapering, or conical, not distinctly clavate (fig. 182), 



except in Coloradoa and Myzapliis, in which they may be slightly clavate 

 at the apex (fig. 315) 5 



Cornicles distinctly clavate (figs. 183, 184) 4 



4. Cornicles long and strongly clavate on one side (fig. 184). Antennae shorter 



than body, with VI spur not longer than III Liosomaphis Walker 



Cornicles slender and but slightly clavate (fig. 183). Antennae never much 



shorter than body, with VI spur longer than III (fig. 258) or with a supra- 

 caudal tubercle (figs. 255, 256) Siphorcoryne Passerini 



5. Third discoidal vein but one-branched (fig. 276). Body without lateral 



tubercles. Cauda long and prominent, being about as long as cornicles. 



Toxoptera Koch 



Third discoidal vein twice-branched. Body with or without lateral tubercles. 



Cauda usually distinctly shorter than cornicles 6 



6. Front of head with a very distinct tubercle (figs. 308, 313). Body long 



without lateral tubercles. Cornicles long and often slightly swollen near 

 apex Myzaphis Walker and Coloradoa Wilson 



7. Front of head without prominent tubercle (fig. 233). Body more rounded 



with lateral tubercles on prothorax and seventh abdominal segment, and 

 oftentimes on some of the anterior abdominal segments Aphis Linn. 



