136 MISCELLANEOUS STUDIES 



312) is long and pointed (ensiform), being slightly more than one-half 

 as long as the cornicles and about one-half as long again as the hind 

 tarsi. 



Measurements : Body length, 1.19 to 1.41 mm. (av. 1.28 mm.); 

 width of thorax, 0.459 to 0.527 mm. (av. 0.487 mm.) ; antennae total, 

 0.85 to 1.156 mm. (av. 1.027 mm.) ; III, 0.255 to 0.34 mm. (av. 0.317 

 mm.) ; IV, 0.1275 to 0.2295 mm. (av. 0.1768 mm.) ; V, 0.119 to 0.17 

 mm. (av. 0.1365 mm.) ; VI, 0.085 to 0.119 mm. (av. 0.1095 mm.) ; 

 spur, 0.119 to 0.204 mm. (av. 0.1695 mm.) ; cornicles, 0.238 to 0.306 

 mm. (av. 0.2574 mm.) ; cauda, 0.136 to 0.187 mm. (av. 0.1588 mm.) ; 

 hind tarsi, 0.119 to 0.136 mm. (av. 0.1205 mm.) ; wing length, 2.482 

 to 2.72 mm. (av. 2.5483 mm.) ; wing width, 0.884 to 1.02 mm. (av. 

 0.9396 mm.) ; wing expansion 5.423 to 5.967 mm. (av. 5.5836 mm.). 

 From tip of wing to base of first branch of cubitus 0.561 to 1.037 mm. 

 (av. 0.8041 mm.) ; from tip of wing to base of second branch of cubitus, 

 0.17 to 0.34 mm. (av. 0.2907 mm.). 



Apterous viviparous female. Head about as long as broad with a 

 large prominent tubercle on the front, this tubercle being considerably 

 larger than in the alate form ; in some individuals it is fully as large 

 as the first antennal segment (fig. 313). Antennal tubercles small but 

 distinct, similar to those of the alate. Antennae (fig. 314) short, 

 reaching only to the third coxae. Ill is the longest segment, followed 

 by the spur, IV, VI, and V. These are all subequal, the formula of 

 the averages being spur, IV, VI, and V. The formulae for seven 

 antennae are S, VI (V, IV) ; S, (VI, V, IV) ; S, V, IV, VI; S, IV (V, 

 VI) ; S, (IV, V), VI; IV (V, VI, S) ; (S, VI, IV), V. The usual 

 primary sensoria are present, but there are no secondary sensoria. 

 The beak is short, reaching only to the second coxae. 



The prothorax is without tubercles. The thorax is normal, as are 

 the legs. The abdomen is long and narrow, without lateral tubercles, 

 and without long capitate hairs as found in some species of Myzus. 

 The cornicles (fig. 315) are long, cylindrical, and slightly tapering 

 toward the apex, or slightly clavate at apex. They are over twice as 

 long as the third antennal segment and over three times as long as 

 the hind tarsi (fig. 317), and half as long again as the cauda. The 

 cauda (fig. 316) is long and ensiform, being slightly more than twice 

 the length of the hind tarsi, and about two-thirds the length of the 

 cornicles. 



Measurements: Body length, 1.275 to 1.615 mm. (av. 1.428 mm.) ; 

 width of thorax, 0.493 to 0.748 mm. (av. 0.6375 mm.) ; antennae total, 

 0.544 to 0.731 mm. (av. 0.6239 mm.) ; III, 0.153 to 0.238 mm. (av. 



