SANBORN : KANSAS APHIDID.E. 2L 



lar, swelling slightly, elongated towards a lip-like opening; 

 15 mm. in diameter ; green while growing, but of a straw color 

 at maturity; walls thick, firm, and succulent. The opening is 

 short and is always parallel with the lower border of the leaf. 

 The petiole bends nearly always to the left around the outer 

 border of the gall at an angle a little greater than a right angle. 

 The young lice remain in the gall until maturity." 



There are many broods of this gall produced throughout the 

 summer. They are seen in the early spring and in the late fall. 

 Very common. 



Pemphigus populicaulis Fitch. Plate V, fig 33. 



Head dark brown. Antennie dark ; length of segments: I, 

 0.05 mm. ; II, 0.05 mm. ; III, 0.16 mm. ; IV, 0.07 mm. ; V, 

 0.09 mm. ; VI, 0.14 mm., including the unguis; unguis alone, 

 0.01 mm. ; total length of antenna', 0.54 mm., extending to 

 the insertion of the front wings. Seusoria transverse, nine on 

 the third joint, and at the lateral inner margin of the third 

 sensoria is a short conspicuous spur, similar to the one on the 

 first sensoria of the popuUtransver.^ii.^. Three seusoria on the 

 fourth joint, three on fifth, with an irregular sensorial near the 

 distal end which contains a few small circular sensoria. On 

 the sixth are five transverse sensoria, while an irregular sen- 

 sorial patch is near the distal end. Eyes are black, ocular 

 tubercles not very prominent, ocelli large, but not conspicuous. 

 Beak extends midway between the pro- and mesocoxse, being 

 0.36 mm. long. 



Prothorax short and lighter in color than the head ; thorax 

 dark brown. Wings hyaline, veins dark, stigma is lighter in 

 the central part than the subcostal vein ; 0.41 mm. long by 0. 14 

 mm. broad. Total wing expansion, 4.50 mm. The two dis- 

 coidals of the hind wing seem to arise from each side of the 

 subcostal. Legs black and rather small in proportion to the 

 body. 



Abdomen greenish and pulverulent. Honey- tubes obsolete. 

 Style not conspicuous but the abdomen ending with a somewhat 

 conical segment. Total length of the body, 3.26 mm. 



This form is very similar to the popiditravsversus but is most 

 easily distinguished by having more sensoria on the antennae. 

 It is gregarious and forms a gall on the cottonwood {Populus 



