1910] Key to the Genera of Aphidinae 321 



inner side, the whole tubercle appearing as a wedge inserted 

 between the head and the first antennal segment. Forehead 

 narrow, outer edge of tubercles appear constricted. Body 

 elongated, wings long. Nectaries about one fourth the length 

 of the body and clavate at the outer end, cauda short, anal lobe 

 broadly rounded. 



Gen. Myzus Passerini 



type A. cerasi Fabricius. 



Antennae about as long as the body and situated on distinct 

 tubercles, third segment as long as spur of sixth; first segment 

 strongly gibbous. Antennal tubercles strongly gibbous on the 

 inner side. Body robust, wings long and broad with cubitus 

 twice forked. Nectaries about one fourth the length of the 

 body, cylindrical, slightly constricted near the tip and slightly 

 curved outward. Cauda less than half the length of the 

 nectaries and tapering. Anal plate broadly rounded. 



Tribe Aphidini 



The characters which separate this tribe from the previous 

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

 as long as the body nectaries and cauda very short. Antennal 

 tubercles, when present, are indistinct or else the nectaries and 

 cauda are small. When nectaries are very long or large the 

 development is limited and the other characters are used to 

 place the genera. Lioso7naphis has large nectaries but the 

 antennae and cauda are very short. Mastopoda has the anten- 

 nae more developed than other genera but the tubercles are 

 wanting. 



I. Nectaries strongly clavate II. 



• — Nectaries tapering and long III. 



— Nectaries cylindrical and long IV. 



— Nectaries very short or obscure V. 



II. Antennae shorter than the body, spur of sixth segment not longer than 



third segment. Nectaries long and strongly clavate on one side. 



Liosomaphis 



— Antennae slightly shorter than the body and with the spur of sixth segment 



much longer than third segment. Nectaries slightly swollen throughout 

 the outer half Hyadaphis 



III. Antennae about as long as the body, nectaries long and tapering and longer 



than the cauda Aphis 



— Antennae shorter than the body, nectaries short and tapering and nearly 



half as wide as long. Cauda short but as long as the nectaries. 



Pergandeida 



IV. Antennae as long as the body, nectaries nearly one fourth the length of the 



body. Tarsi and claws atrophied Mastopoda 



