2 NEW CALIFORXIAX APHIDIDAE 



and San Jose, as Callipterus (Calaphis) castaneae Fitch (Buckton).^ 

 However, it proves to be distinct from this species as brought 

 out by a study of specimens together with Baker's paper on the 

 genus Calaphis.^ The chief differences are the absence of antennal 

 tubercles, thus placing the species in the genus Myzocallis rather 

 than Calaphis, and the fact that the spur of the sixth antennal 

 segment is scarcely twice as long as the base, while in C. castaneae 

 (Fitch) the spur is practically four times as long as the base. 

 There is little doubt but that the California species is distinct, so 

 the author describes it herewith under the name of Myzocallis 

 davidsoni new species, naming it after Mr. W. j\I. Davidson of the 

 Bureau of Entomolog5^ The alate stem mothers appear rather 

 late in the spring, usualh" during the latter part of April or the 

 first of ]\Iay. These reproduce parthenogenetically throughout 

 the summer, both alate and apterous viviparous females being 

 produced. In the fall, usually during October and November, 

 sexual forms appear, the males being alate and the oviparous 

 females apterous. The sexupara are alate, at least in all col- 

 lections seen by the writer in which there were sexual forms, 

 onh' alate presexual forms were present. The writer has never 

 observed the eggs, but the}' are laid during October and Novem- 

 ber on the bases of the buds, or on roughened parts of the bark 

 of the branches, and even of the trunks of the trees. In Sep- 

 tember 1915, the writer found an infestation of this species on 

 Quercus pedunculata in Berkelej^, and in April 1916, Essig took 

 it again from the same trees. Davidson* described the alate 

 male and the apterous oviparous females under the name Cal- 

 aphis castaneae (Buckton), from specimens taken in San Jose in 

 November. Following is a description of the alate and apterous 

 viviparous females, taken from specimens collected by the writer 



2 Clarke, W. T., List of California Aphididae, Can. Ent., 35: 249, 1903, Cal- 

 Kpterus castaneae Fitch, list; Davidson, W. M., Further Notes on the Aph- 

 ididae Collected in the Vicinity of Stanford University, Jour. Econ. Ent., 3: 

 376, 1910, Callipterus castaneae Buckton, list; Davidson, W. M., Aphid Notes 

 from California, Jour. Econ. Ent., o: 405, 1912, Calaphis castaneae (Buckton), 

 desc. sexes; Essig, E. O., Aphididae of Southern California, Pom. Jour. Ent., 

 4: 760, 1912. 



3 Baker, A. C, A synopsis of the genus Calaphis, Proc. Ent. Soc. Washington, 

 18: 184-189, 1916. 



* Davidson, W. M., Aphid Notes from California, Jour. Econ. Ent., o: 405, 

 1912. 



