A SYNOPSIS OF THE APHIDIDAE 99 



0.408 to 0.45 mm. (av. 0.4186 mm.) ; cornicles, 0.221 to 0.255 mm. 

 (av. 0.2401 mm.); cauda, 0.15 mm.; hind tarsi, 0.12 to 0.135 mm. 

 (av. 0.1275 mm.). 



Alate viviparous female. Prevailing color pale to apple green. 

 Head, antennae, thorax, marginal spots on abdomen, cornicles, tip of 

 cauda, femora, and tarsi all black. Antennae (fig. 289, 290) with the 

 usual primary sensoria on V and VI and the usual accessory sensoria 

 on VI. IV without sensoria and III with from 6 to 11 fairly large 

 circular secondary sensoria, the usual number being 8 (fig. 290). In 

 this character it differs most markedly from the Main specimens, 

 which have from 12 to 18 sensoria on III and from none to several 

 on IV. The antennae are slightly shorter than the body although 

 practically of the same length. Ill is the longest segment, closely 

 followed by the spur, then by IV, V, VI, I and II. Ill and the spur 

 are subequal, or either one or the other may be slightly the longer. 

 In Patch's drawing V is a little longer than IV. In the California 

 specimen IV is always slightly the longer of the two. In all the 

 California specimens the antennal segments are all a little shorter 

 than in the Maine material. Lateral tubercles are present on the pro- 

 thorax; they are always present on the seventh abdominal segment, 

 and may be present on any of the first few segments of the abdomen 

 as well. In one case they were observed on the second and seventh 

 segments, in another on the second, third, and seventh, in still another 

 on the fourth, fifth, and seventh, and in a fourth case on the first, 

 second, third, fourth, and seventh segments (fig. 292). The wings 

 and venation are normal, with the second branch of the cubitus arising 

 nearer to the tip of the wing than to the base of the first branch (fig. 

 291). However, it is not quite so close to the wing tip as in the Maine 

 specimens. The cornicles (fig. 292) are long and cylindrical. They 

 are equal to or slightly shorter than V, and from one and one-half to 

 two times as long as the hind tarsi. The cauda (fig. 292) is more or 

 less ensiform, about one-half as long as the cornicles, reaching to the 

 tip of the cornicles, and subequal to or slightly shorter than the hind 

 tarsi. 



Measurements (of specimens mounted in Canadian balsam) : Body 

 .length, 1.53 to 1.65 mm. (av. 1.585 mm.) ; width of thorax 0.697 to 

 0.765 mm. (av. 0.731 mm.), antennae total, 1.568 mm.; I, 0.068 to 

 0.085 mm. (av. 0.0765 mm.) ; II, 0.051 mm.; Ill, 0.331 to 0.408 mm. 

 (av. 0.3644 mm.) ; IV, 0.238 to 0.289 mm. (av. 0.2817 mm.) ; V, 0.221 

 to 0.247 mm. (av. 0.2295 mm.); VI base, 0.085 to 0.111 mm. (av. 



