374 



JOURNAL OF ECONOMIC ENTOMOLOGY 



[Vol. 3 



Pemphigus populiconduplifolius Cowen. Making galls on the poplar 

 (Populus trichocarpa) in April. The stem mother is olive green, with 

 darker longitudinal stripes. The eyes are small and black. The 

 terminal portion of the abdomen is rather bristly. Cauda and corni- 

 cles absent. Beak just reaches second coxae. The head is black, the 

 antennse hyaline, and the legs dusky. I doubt if the specimens ex- 

 amined were full grown so do not give any measurements. 



Pemphigus populimonilis Riley. Abundant in Tulare County on 

 Populus fremonti during the summer months at least. 



Schizoneura lanigera Haus. On cultivated apple. 



Schizoneura querci Fitch. Found in considerable abundance on the 

 live-oak (Q. agrifolia). 



Schizoneura americana Riley. Several years ago this insect was so 

 abundant on the elms on the Stanford University campus as to almost 

 kill the trees. At the present time it is not at all common. 



Lachnus viminalis Fonsc. On Salix sp. Much parasitized by an 

 Ephedrus. 



Lachnus abietis Fitch. This large aphis is at times extremely com- 

 mon and at other times it appears to be almost totally exterminated 

 by Syrphid larvte. I have never found any winged forms although 

 my observations on colonies of the Lachnus have extended over 

 eighteen months. On Abies concolor. 



Lachnus pini-racliatce Davidson. On the needles and twigs of Pvnus 

 radiata. 



Lachnus occidentalis Davidson. Abundant on the smaller branches 

 and twigs of the spruce {Abies grandis) secreting a woolly material 

 which causes the twigs to assume a bluish color. Although I have had 

 colonies under observation for two years I have never seen the winged 

 form. The Syrphid flies Syrphus arcuatus and 8. opinator exact a 

 very large toll from this aphid and are themselves frequently para- 

 sitized by a large Braconid. 



