414 ENTOMOLOGICAL NEWS. [NOV., '17 



Early Spring Syrphidae in California and a new 



Pipiza (Dip.). 



By W. M. DAVIDSON, U. S. Bureau of Entomology, Sacra- 



mento, Cal. 1 



The writer has been collecting Syrphidae in the coastal dis- 

 tricts of central California the past six years and has there- 

 from secured considerable data on the appearance of these 

 flies in spring. This paper aims to discuss those species which 

 in the adult stage reach their maximum numbers before April 

 and to briefly note others which have been taken in flight dur- 

 ing the first three months of the year. The writer is aware 

 of the arbitrariness of fixed dates in connection with the habits 

 of insects and hopes exception will not be taken to his use of 

 them here. 



The average daily mean temperature of February is about 

 50 F. and of March about 54 F. in the region above cited. 

 Frosts are comparatively unusual after February 15 and in 

 March the temperature rarely drops below 35 F., while fre- 

 quently arising to over 70 F., yet there is probably greater an- 

 nual variation in the March meteorological conditions than in 

 those of any other month. 



Syrphidae in this locality are most abundant on the wing 

 in the months in which most of the wild flowering plants 

 bloom April and May and thereafter are on the wane dur- 

 ing the dry summer until September and October, when a "re- 

 vival" occurs and the autumn blossoms such as BaccJiaris pil- 

 Inlaris Roe. and Aster chamissonis Gray yield good collecting. 

 The writer has taken thirty-two species of Syrphidae in March 

 as against fifty-eight in April and May combined. It is prob- 

 able that several of the species collected in April but not in 

 March are occasionally abroad in the earlier month. 



In normal seasons five species have been observed to reach 

 their maximum numbers in the adult stage before April. These 

 are Crioprora cyanclla O. S., Cr. alope.r O. S., Chcilosia acci- 

 dent alls Will., Spheglna sp. (near rnjk'cntris), and 



1 Published with the permission of the Secretary of Agriculture. 



