686, 



under surface of the leaf ; they suck the sap, causing the leaf to wither. 

 The eggs are laid in the newer leaves and the winter is passed in this 

 stage. At Ithaca, the eggs hatch in late May or early June ; in 1908, 

 first, second and third stage nymphs were observed on 2nd June. 

 The nymphs feed in groups ; in the insectary, the nymphal stage 

 lasted from 25 to 34 days, and is probably a little longer under outdoor 

 conditions. These insects can be readily controlled by a soap and 

 water spray, at the rate of 1 lb. soap to 10 U.S. gals, water. The spray 

 should be directed against the under side of the leaves and applied 

 as soon as the nymphs are observed. More than one application 

 during the season may be necessary. In the case of rhododendrons, 

 the spray should not be applied while the sun is shining or the leaves 

 will be scorched. 



Davidson (W. M.). Little-known Western Plant-Lice. I.—Jl. Econ. 

 Entom., Concord, viii, no. 4, August 1915, pp. 419-429, 3 plates. 



Phylloxera salicola, Pergande, occurs in California on Salix lasiolcpis, 

 Benth. Infestations are mostly confhied to the axils of the buds on 

 the twigs, but in one instance a heavy infestation occurred on the 

 bared roots of a willow growing on the bank of a stream. The roots 

 were about | inch in diameter and the aphids occurred in all the small 

 cracks in the bark. No nymphs or winged forms were found. Accord- 

 ing to Pergande, some of the eggs deposited by apterous females are 

 sexual. In California no sexual forms have been found and probably 

 the asexual generation reproduces throughout the winter. Colonies 

 comprising eggs and lice in all stages were collected on 6th November 

 1913, 3rd February 1914, and TSth October 1914. P. populmia, 

 Pergande, infests the limbs and twdgs of Populvs tricJwcarpa and 

 P. fremontii, Wats. The individuals are covered with a white cotton- 

 like substance and are found in cracks in the bark. They also invade 

 old galls of Thecabius populicaulis, Fitch. Specimens were collected 

 on 20th April and 4th May 1914, in California. In the latitude of 

 San Francisco, the sexuparae of Thecabius populicauUs have been 

 observed under poplar bark in late winter and spring. The single egg 

 is laid in a crevice of the bark and covered by cottony filaments 

 excreted by the female. Incubation in May takes about two weeks. 

 The fundatrix ascends the tree and settles at the base of a leaf. The 

 petiole swells at the point of attack and a gall gradually forms around 

 the growing Aphid. A Syrphid fly, Pipiza pisticoides, Will., has been 

 bred from a larva found feeding on the sexual forms of this Aphid. 

 The winged spring migrants in the latitude of San Francisco are found 

 in the galls from May to November. The sexuparae of Prociphilm 

 fmxini-dipetalae, Essig, were taken under the bark of Fraxinus oregana 

 on 16th March 1915. Nearly all the winter eggs had hatched on this 

 date. The young stem-mothers occurred higher up on the tree either 

 in cracks in the bark or on the expanded foliage. The spring migrants 

 of P. fraxini-dipetalae have been taken on ash and olive and occur all 

 over California. Euceraphis gillettei, sp. n., occurs in California on 

 the underside of the leaves of Ahuis rhombifolia and in Colorado on 

 Bstida foi'itina.Us and Alnns sp. EmaUipferus flavus, Da\idson, was 

 collected in October from the leaves of Alnus rhombifolia. The eggs 

 are laid in groups at the axils of the new buds on the twigs or canes. 



