A SYNOPSIS OF THE APE I Dl DAE 149 



and June, 1915, it was especially so on a row of elms on the campus 

 of Stanford University. At that time stem mothers, nymphs, and 

 alate spring migrants were present in the galls. By the last of June 

 all of these had flown away, leaving the galls empty. According to 

 Baker elm is the only host plant of this species. 



174. Eriosoma lanigerum (Hausman) 



Hausman, Mag; Ins., vol. 1, p. 440, 1802. Aphis (orig. desc.). 

 Davidson, Jour. Econ. Ent., vol. 2, p. 299, 1909. Schizoneura (list). 

 Davidson, Jour. Econ. Ent., vol. 3, p. 374, 1910. Scliizoneura (list). 

 Baker, U. S. Dept. Agr., Office Sec'y, Report 101, pp. 11-16, 1915 (desc. 

 and biology). 



Record. Pyrus mains, throughout the state. 



Wherever apple trees are found in the state this woolly aphis is 

 also found ; the white masses on the trunks and leaves being very con- 

 spicuous, the colonies on the roots more injurious but less conspicuous. 

 In California only the -apple has been found to be attacked. The 

 winter is passed by young nymphs on the roots. As the warmer 

 weather of spring comes these migrate up the trunks and out on 

 the branches and twigs. Here they feed throughout the summer. In 

 the fall there is a downward migration, and occasionally a fall 

 migrant is seen. Whether or not these fly to elms as in other parts of 

 the country, is not known, but none have ever been observed on elm. 



175. Eriosoma languinosa (Hartig) 



Hartig, Zeitschr. Ent., vol. 3, p. 359, 1841. Aphis (orig. desc.). 



Baker and Davidson, Jour. Agr. Res., vol. 6, pp. 351-360, 1916. E. pyricola 



n.sp. (desc.). 

 Baker and Davidson, Jour. Agr. Res., vol. 10, pp. 65-74, 1917. E. pyricola 



B. & D. (desc. and biology). 



Records. Pyrus communig, TJlmus campestris; central California. 



In 1916 Baker and Davidson described a species of Eriosoma that 

 attacks the roots of pears throughout the central part of the state, 

 naming it E. pyricola. Later Davidson found that a species common 

 on Ulmus campestris was the alternate form of this species. This elm 

 form checks up very favorably with specimens of E. languinosa Hartig 

 from Europe, and is undoubtedly identical. Thus the name pyricola 

 will have to be dropped in favor of languinosa. These elm galls are 

 of a rather peculiar shape, and, as Patch writes, they have the appear- 

 ance of a bonnet. 



