THE GRAPE PHYLLOXERA IN CALIFORNIA. 27 



aphis vastatrix Planchon, and in the same year Signoret (22) placed 

 the species vastatrix in the genus Phylloxera de Fonscolombe. The 

 year following Westwood (23), in England, described the insect as 

 Peritymbia vitisana, but in a later article the same year he placed 

 his species in synonymy as follows : Peritymbia vitisana Westwood= 

 Pemphigus vitifoliae Fitch, Dactylosphaera ( ? ) vitifoliae Shimer, 

 and Phylloxera vastatrix Planchon (19). Until 1900 the name gen- 

 erally recognized by writers had been Phylloxera vastatrix Planchon. 

 In 1900 Del Guercio (12), in Italy, erected the genus Xerampelus to 

 receive the grapevine species, which he therefore called Xerampelus 

 vastator. This genus has not been recognized by all later authors. 

 Grassi (11, p. 12) would retain Shimer's proposed genus Viteus as a 

 subgenus to Phylloxera, and would thus name the species Phylloxera 

 {Viteus) vastatrix. The present writers are inclined to retain the 

 specific name vitifoliae Fitch on account of its evident priority over 

 Planchon's more widely known vastatrix, and notwithstanding the 

 objections raised by authors as to its orthographical correctness 

 (vitisfolii and vitifolii have been preferred and written). As to the 

 generic title, it has been decided that Phylloxera will be retained, 

 the question of the subdivision of the genus being left to those who 

 have had more opportunity to study the specific ramifications of 

 this group. 



The synonymy of the grape phylloxera as understood by the 

 writers is therefore as follows : 



Phylloxera vitifoliae (Fitch). 



Pemphigus vitifoliae Fitch, 1855-56. 

 Dactylosphaera (?) vitifoliae (Pitch) Shimer, 1867. 

 Viteus vitifoliae (Fitch) Shimer, 1867. 

 Rhyzaphis vastatrix Planchon, 1868. 

 Phylloxera vastatrix (Planchon) Signoret, 1868. 

 Peritymbia vitisana Westwood, 1869. 

 Xerampelus vastator (Planchon) Del Guercio, 1900. 

 Viteus vastator (Planchon) Grassi et al, 1912. 



BIOLOGY OF THE GRAPE PHYLLOXERA IN CALIFORNIA. 



THE LIFE CYCLE. 



The complete life cycle of the grape Phylloxera under natural con- 

 ditions, i. e., on the wild vines of eastern North America, is extremely 

 complicated (fig. 4). It is not the intention of the authors to enter 

 into all the ramifications of this cycle in the present paper, but it 

 may be said that the following are the main forms that occur: (1) 

 The stem mother or fundatrix, which hatches in spring from the 

 winter egg, ascends to an early leaf, settles on the upper surface, 

 and causes to .form around her a pocketlike gall opening on the 



