272 



CONNECTICUT GEOL. AND NAT. HIST. SURVEY. 



[Bull. 



whereas others are very sedentary. The sexual forms do not vary 

 greatly from the viviparous ones. In nearly all of the subtribes 

 the males are winged, but in the Saltusaphidina they are apterous. 

 In the other tribes several kinds of males may be found in the same 

 species. Apterous males and fully winged males may be seen and 

 various types of intermediate males also occur. The oviparous 

 females are nearly always apterous but in the Phyllaphidina 

 winged oviparous females are present in the genera Tamelia and 

 Neophyllaphis. The latter genus, however, does not occur in New 

 England. 



The wing veins are not greatly reduced in any members of the 

 tribe. Considerable variation, however, is shown in the cornicles, 

 although they are never long and prominent as in the Aphidini. 

 The usual form is the truncate cornicle seen in Myzocallis, Chaito- 

 phorus, etc. Very often they are sculptured. In some cases they 

 are reduced to small cup-shaped structures and again they may be 

 represented by mere rings. 



r\ 



I 



Fig. 26. Structures of aphids of the Subtribe Pterocommina. (1-2) 

 Melanoxanthcrium medium Baker. (3-4) Pterocomma populea Kaltenbach. 

 (5-6) Mclanoxantherinvi smithiae Monell. (7-8) Melanoxantherium bicolor 

 Oestlund. (9-10) Melanoxantherium beulahensis Cockerell. (11-12) 

 Melanoxantherium flocculosum Weed. (13-14) Melanoxantherium salicis 

 Linnaeus. (15-16) Melanoxantherium populifoliae Fitch. All greatly 

 enlarged. Drawing by Dr. A. C. Baker. 



