A SYNOPSIS OF TEE APHIDIDAE 53 



while the author feels that it is better associated with the Aphidini, 

 inasmuch as the antennal tubercles are very small and more or less 

 indistinct and as the antennae are scarcely as long as the body. Van 

 der Goot's genus, Myzaphis, has been accepted for the two species, 

 Myzus rosarum (Walker) and Aphis abietina Walker, and is included 

 with the Aphidini. The species Aphis nymphaeae Linn., which Wil- 

 son uses as the type of Rhopalosiphum, has been taken from this genus 

 and placed in Siphocoryne, chiefly because of the apparent absence 

 of antennal tubercles and of the presence of distinct tubercles on the 

 seventh abdominal segment. Therefore Aphis persicae Sulzer takes 

 the place as type of the genus Rhopalosiphum. 



KEY TO CALIFORNIA GENERA 



1. Cornicles cylindrical, or at most but very slightly swollen on one side (figs. 



122, 152 ) 4 



Cornicles distinctly swollen toward apex, or clavate (figs. 109, 113, 119) 2 



2. Antennal tubercles very large and tapering but not gibbous on the inner side; 



the bases of the antennae being more or less approximate (fig. 107). 



Nectarosiphon Schouteden 



Antennal tubercles distinct, but not large and tapering as above, being more 



or less toothed or gibbous on the inner side; the bases of the antennae not 

 approximate (figs. 108, 111) 3 



3. Antennal tubercles short and wedge-shaped, the outer side not evident (fig. 



108). Cauda ensiform and of medium size. Antennae at most but slightly 

 longer than the body Rhopalosiphum Koch 



Antennal tubercles short, but not wedge-shaped (fig. 111). Antennae con- 



siderable longer than the body. Cauda very large and long. 



Amphorophora Buckton 



4. Antennal tubercles large and as long on the outer as on the inner side (fig. 



106) 5 



Antennal tubercles with outer side shorter than inner, or not evident (figs. 112, 



115, 116) 7 



5. Cornicles tapering, longer than cauda which is ensiform (fig. 152). "Wing 



venation regular, with third discoidal twice-branched. 



Macrosiphum Passerini 



Cornicles and cauda variable. Wing venation irregular and very striking with 



veins either wanting or combined, and shaded 6 



6. Antennal tubercles with short upper inner angle. Cauda shorter than cornicles 



and tapering. Stigmal and third diseoidal veins meet in a broad dark 

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

 (fig. 110) Idiopterus Davis 



Antennal tubercles with small rounded tubercle at the upper inner angle. 



Cornicles slightly constricted in the middle and at the tip. Wing venation 

 variable, but usually the stigmal and third discoidal veins are partly 

 joined and form a distinct, closed, four-sided cell Pentalonia Coquerel 



7. Antennal tubercles and first antennal segment with a strong tooth on the 



inner side of each (figs. 115, 116). Cauda short and tapering (fig. 118). 

 Cornicles cylindrical and tapering slightly with tip outcurved (fig. 117). 



Rhorodon Passerini 



