PINK AND GREEN APHID OF POTATO. ; 209 



females, and males, — whether of the green or pink variety, and 

 regardless of the food plant upon which they have developed. 

 The cornicles of the immature individuals are not so marked. 

 The antennae of the apterous females are a little swollen at the 

 proximal part of III, where a few sensoria are placed ; those of 

 the alate females have the sensoria in a single row not extending 

 to the distal tip of III. The wing veins are clear cut and well 

 defined though slender. 



The foregoing are the general recognition marks. There is 

 no structural difference between the spring and the fall indi- 

 viduals great enough to lead one to think they might be different 

 species; though there is a range in size, influenced by food plant 

 or other conditions, great enough to cause hesitation in deter- 

 mining certain collections unless the progenitors are known. 

 The measurements, therefore, in the following descriptions can 

 only be taken as approximate. 



Macrosiphum solanifohi. Winged I'lzn parous female, green varieiy.— 

 Head yellowish green. Beak tj^pically barely reaching second coxa, 

 though in some collections a liitttle longer. Antennae, proximal seg- 

 tnentis pale green, distal segments dark; length of segments: III, .88 to 

 .c6 mm. ; IV, .y6 to .9 mm. ; V, .64 to .72 mm. ; VI, base .16 to .2 mm. ; VI, 

 spur .96 to 1. 12 mm. ; total length I to VI, 3.6 to 4.05 mm. Ill with single 

 row of sensoria S0'me^\rha)t irregular in size nurtibering 18 or a few 

 more or less, not extending to distal end. Prothorax and thorax light 

 yellowish green, lobes brownish. Wings hyalirje, veins dark brown, very 

 slender and clear cut, stigma pale brown. Total wing expansion 8.1 mm. 

 Legs with proximal part of femora and tibiae pale, tarsi and, distal parr 

 of femora and tibiae dark. Tarsi .16 to .2 mm. Abdomen light green 

 unmarked dorsally or venitrally. Cornicles, with proximal portion green 

 and distal portion dark brown, imbricated for more than three-fourtlis 

 it."- length but strongly reticulated at tip, cylindrical, length .95 mm. or 

 about five times length of tarsus. Cauda light green, ensilorm, lengtli 

 .48 mm. or about one-half length of cornicles. Total length of body to 

 distal tip of Cauda and exclusive of antennae 2.9 to 2)-37 "ensm. 



Winged viviparous female, pink variety. — Head light yellowish. An- 

 tennae with I and II light yellowish, rest dark. Sensoria as with the 

 green variety. Porthorax and thorax light yellowish pink. Abdomen 

 pale pink. Cornicles light yellow with tips dusky and strongly reticulated. 

 Cauda pink. Measurements the same as with the green variety. 

 . Apterous viviparous female. — Color either pink or green as with the 

 winged viviparous f OTm. Antennae, length of segments : HI, .8 to .96 

 inm. ; IV, .72 to .88 nmi. ; V, .56 to .72 mm. ; VI, base .16 to .2 mm.; VI 

 .'^nur .96 to 1.2 mm.; total length of segments I to VI, average about 4.05 

 mn-i. HI slightly swollen at basal third where i to 5 sensoria occur.- Cor- 



