PERGANDE — NORTH AMERICAN PHYLLOXERIN^. 215 



The gall of this species is one of the most common and numer- 

 ous on the lea^ves of Hicoria (^Carya) alba, and probably some 

 other species of the genus in the states of Missouri and Illinois, 

 extending at least as far south as Tennessee and probably 

 throughout most of the states bordering the Mississippi. It seems 

 to be exclusively a western species, and is at times so extremely 

 abundant as to cover completely every leaf upon a tree, the 

 leaves becoming much dwarfed and distorted. On some small 

 leaflets, about 2 inches long by i^ inch wide, more than 300 of 

 these galls were counted. 



The fully grown galls vary in height and diameter at base from 

 1-5 ""■ Those more, densely crowded are narrower at base and 

 higher in proportion. They are conical or tooth-like above and 

 frequently lean over to one side. The under side is more or less 

 prominently convex and more or less prolonged at the centre, 

 with the nipple often, also, inclining to one side. The orifice is 

 either round or oval, closely fringed with pale hairs, and tightly 

 drawn together till maturity. The walls are rather tough and 

 leathery. The color of the galls when younger is greenish-yellow 

 to reddish, becoming gradually brown or black,- and brittle after 

 the insects have left. 



Stem-mother. — lyength about o.6™™-. Body almost globular. 

 Color, orange ; legs and antennae dusky. Eyes, dark purple. 

 Surface of body quite densely covered with rather coarse, some- 

 what conical granules, though less dense than in the stem-mother 

 of Ph. deplanata, the granules interspersed with a few stiff hairs, 

 most numerous about the anal segment, and some of them capi- 

 tate. Antennae rather stout, the third joint about as long as the 

 tibiae and somewhat clavate, with about 18-20 rather coarse and 

 apparently scaly annulations, and provided at tip with two short 

 hairs. I,egsratber long and stout. 



Migratory female. — I^ength of body 0.6-0.8'"™-. Expanse 

 of wings 2.3-2.8™™-. Color, orange j^ellow. Head and thorax 

 •blackish, the head often paler. Eyes purplish ; the two inner 

 ocelli red, the frontal one colorless-, all bordered with black at 

 inner side. Antennae and legs faintly dusky. Wings pale brown- 

 ish ; stigma and veins darker ; the veins shaded with dusky. 

 Venation normal, stigmal vein and cubital branch alinost parallel. 



