8 Thomas Albert Williams 



Cotypes in collection of the University of Nebraska (no. 4) 

 and of the U. S. National Museum (no. 120). 



4. Pemphigus balsamiferae n. sp. 



Stem-mother: General color pale green; head, antennae and legs dusky 

 black. Antennae 4-jointed, joint III longest, IV with very short claw. 

 Abdomen swollen, broadly oval, generally pointed posteriorly, with six 

 longitudinal rows of white spots (white flocculent when fresh) above, 

 and a marginal row of small brownish spots. 



Larva pale green. Pupa pale green with paler thorax, wing-pads, legs, 

 and antennae ; legs and antennae become darker with age. 



Winged female: Head, legs, antennae and thorax brown to black; neck 

 and abdomen green; joints I and II subequal, IV, V and VI club-shaped, 

 III with 8-10 narrowly elongate transverse sensoria, IV with 3-4, V with 

 3, VI with none. Joints III-VI more or less annulate. Wings with heavy 

 black costal and subcostal veins, first and second discoidals only moder- 

 ately near at the base, third discoidal obsolete for about one third its 

 length. Stigma dusky acute at inner end, outer end angled, stigmal vein 

 curved slightly. 



Squaw Creek, June 24, 1890. On Popitlus balsamifera, form- 

 ing an irregular semiglobular or more or less elongated gall on 

 the under side of the leaves, with an irregular opening on the 

 upper side. 



Cotypes in collection of the University of Nebraska (no. 5) 

 and of the U. S. National Museum (no. 121). 



5. Pemphigus fraxinifolii Riley. 



Riley, Bull. U. S. Geol. Sur. Ter., Vol. VI, p. 17 (1879)- 



Thomas, Ins. 111., 8th Rep., pp. 146, 210 (1879). 



Oestlund, Syn. Aph. Minn., p. 23 (1887). 

 Winged female: Alar expanse 5.70 mm. Head and thorax dusky; abdo- 

 men dark green. Antennae reaching by the length of the apical joint 

 beyond the costal base of front wings; inconspicuously annulated and with 

 joints III to VI but moderately narrowed at base; III as long as IV and 

 V together; VI (including unguis) nearly three fourths as long as V, 

 with the unguis distinct and of normal length. Scutellar lobes of meso- 

 notum broad and well marked. Legs normal. Wings hyaline ; stigma 

 linear, or not wider than subcostal space, yellowish and poorly defined 

 anteriorly ; veins very slender and subhyaline, the stigmal most distinct, 

 starting a little in front of middle of stigma and but faintly curved; 

 cubital almost invisible but not obsolete at base, where it nearly joins the 



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