Pomona Colleoe Joiknai. of Entomolociv 



705 



width ()..S(t inin. Stipinal vein iiiKliilati'. nrisiiif; near llif tip of thr stif^iin and 

 ratliiT sliarplv curved downward \nitil near tlii- middle, tlii-n curves upwardly 

 until near the tip where it turn down, curves well rounded and not at nil abrupt, 

 lirowri : first discoidal arisinj; near the middle of the subcostal vein and extending 

 almost straijjht to the wing margin at an atigle of nearly V'> degrees to it, usuallv 

 curves slightly inwardly towards the body; second discoidal rises near the base 

 of the tirst, and extends nearly parallel to the third discoidal, curves slightly 

 inwardly, much longer (nearly twice) than the first discoidal; third discoidal obso- 

 lete at base, nearly |)arnllel with second discoidal but diverges towards the tip of 

 the wing, the tip is midway between tips of the stigmal and second discoidal ; 

 veins brown or amber. Secondary — Length .S.'i nnn., width (1.9 nun.; suln-ostal 

 with two downward curves, one at the bases of the discoidals and the other two- 



03^/SBfc^B^i:iQif(:i 



'■■■HiiiJ'iTi ' Tj ^ 



Figure 224. Pemphigus populimonilis Riley 



thirds its length; discoidals .arising at one-third the length of the snb-costal. 

 where it makes a rather sharp bend, from a rather narrow brown or amlwr sj)ot, 

 their bases close together; first discoid;il curving tow;irds the tip. while the set-- 

 oiid curves toward the b.-ise of the wing: veins amber. Cauda — Well rounded and 

 inconspicuous. 



yiiimphs — The nymphs of the winged viviparous fem.'iles an- often very large 

 U-fore their wings .'ire fully devi^loped. 'i'lie color varies from a light yellowish 

 to a dusky green. The he:id is usually darker. The entire body is covered with 

 a very fine white powiler .-md there is no sign of tloec'ulenee iinlil the .-idull stage 

 is reached. 



APTK.Ilors VlVIPMtors fkm\i.k> 



.\pp;irently there .-ire no .iplerous forms o<-eurring in the galls observed in 

 this locality. 



//o*/i- -Infesting the common Cottonwood {/'opiilus trirhornrpa T. & G). 

 forming rows of the bead-like galls on the leaves. The galls are formed more 



