Pomona College Journal ov Entomology 



597 



thirds, wliik- those of M. dcstrurtor an' dusky only at tlic tiijs. Tlie styles of M. 

 citrifolii are the smallest, of M. rosac next in size (both of these are quite hairy) 

 while those of M. destructor are much larger and are nearly destitute of hairs. 

 The general ajjpearanee of M. rosae is also easily told by the rosy forms and by the 

 dark legs, the black markings of the head, thorax, and abdomen. Neither of the 



U^ 



Figure 194. Details of Macrosiphum citrifolii (a, b, g, h, m, n) ; Macrosiphum 

 rosae (c, d, i, j, o, p) ; Macrosiphum destructor (e, f, k, 1, q, r) 



latter forms have these characters, except the darkened areas on the legs and 

 these are much fainter. 



Natural enemies — Macrosiphum citrifolii Ashni. is very effectually held in 

 check in California by the predaceous ladybird beetles, Coccinella californica Mann, 

 Hippodamia convergens Guer. and Coccinella ahdominalis Say and by the larva- 

 of the Syrphid Flies S//rphus americanus Wied., Allograpta obliqua Say., and 

 Lasiophthicus pyrastri L. 



I am indebted to Mr. John .Tune Davis for his aid in the determination of 

 this species. 



