The Aphididae of Nebraska 7 



depending on the age of the insect, being much greater when the abdomen 

 is full of eggs. 



On hickory (Carya amara), Wabash, June i, 1889, when only 

 the foundress of the colony and the very young larvae were 

 found. On C. porcina, Ashland, May 24 and June 11, 1890. On 

 the latter date plenty of winged forms were found in the galls 

 which were breaking open at the apex to allow the lice to escape. 

 The galls are rather large, more or less elongated masses on the 

 young twigs, petioles, and the base of the midveins of the leaves. 

 In some cases they assume a somewhat conical outline. The 

 younger trees and shoots are most affected, often nearly the en- 

 tire foliage being distorted by the galls. 



Specimens in collection of the University of Nebraska (nos. 



1. 2) and of the U. S. National Museum (no. 159). 



2. Phylloxera vastatrix Planch. 



On Vitis cordifolia, Fremont, July 31, 1890, specimen no. 3, 

 University of Nebraska collection. 



Genus Pemphigus 



3. Pemphigus alnifoliae n. sp. 



The young are light yellowish green, legs and antennae whitish. 



Pupae similarly colored. 



Winged female: Head and thorax black. Head rather small. Antennae 

 brownish black with white rings at each joint and sometimes V and VI 

 are quite pale colored, III equals IV and V, IV, V and VI subequal, VI 

 with its spur about two thirds III; IV, V and VI club-shaped, III cylin- 

 drical. Antennae on quite prominent, pale tubercles. Eyes black. Wings 

 with yellow insertions and yellowish stigma, first and second discoidals 

 starting from nearly the same place, slightly curved. Cubital moderately 

 distinct for its whole length, starting from nearly the same place as the 

 second discoidal. All of the discoidals as well as the stigmal vein with 

 smoky borders. Abdomen light yellowish green. Legs dusky. Length 

 of antennae 0.10 mm., length of body 3.54 mm. 



Stem-mother: Dark green; head, antennae and some markings on thorax 

 dusky. Abdomen swollen, ovate or oblong. Length of body 3.75 to 4.00 

 mm. All forms more or less covered with white flocculency. 



On leaves of Amclanchier alnifolia, causing them to curl and 

 form a pseudogall. War Bonnet Canyon, June 21, 1890. 



91 



