OSTEN SACKEN ON WESTERN DIPTERA. 325 



Front not unusually projecting ; no conspicuous area of larger facets 

 in the middle of the eye of the male ; middle sized species, 

 with three pairs of yellow abdominal spots, the second and 

 third lunate : 

 Face with a broad brown stripe over the tubercle 5 eyes pubes- 

 ceut;* abdominal lunules deeply emarginate in the mid- 

 dle 2. intrudens n. sp., $ . 



Face with a small brown stripe over the tubercle; eyes 

 glabrous; abdominal lunules of nearly equal breadth, 



3. lapponicus Zett., $ . 

 II. The second and third abdominal cross-bands are not interrupted ; 

 eyes glabrous : 

 The second and third cross-bands do not reach the lateral margin of 

 the abdomen: 

 Face with a brown stripe in the middle on the tubercle ; abdom- 

 inal cross-bands broad 4. americanus Wied., $ . 



Face and cheeks altogether yellow ; abdominal cross-bands 



rather narrow 5. opinator n. sp., $ ? . 



The second and third cross bands reach the lateral margin of the 

 abdomen ; in the male, all the femora are red to the very base, 



coxse and trochanters being black 6. protritus n. sp., $ . 



1. Syrphus pyrastri {Syrphus pyrastri Linne, Fauna Suecica; Syr- 

 1 phus transfugus Fabricius, Ent. Syst., iv, 306; Syrphus affinis Say, 

 i Journ. Acad. Phil., iii, 93, 9). 



The Californian specimens do not show any difference from the Euro- 

 pean ones, which I had for comparison, except that the abdominal yellow 

 spots are a little narrower; and even this difference does not exist in 

 my specimen from Colorado. Macquart (Dipt. Exot., ii, 2, 83 and 

 ! 88) records the same species from Chili. 



It occurs everywhere in California, is not rare, and begins to appear 

 very early. I have specimens from Santa Barbara, February 10 ; Santa 

 I Monica, February 18; Petal uma, April 28; San Eafael, May 29; Yo- 

 1 Semite, June ; Webber Lake, July 26 ; Salt Lake, Utah, August 1. I 

 also have it from Southern Colorado (W. L. Carpenter). Say had it 

 I from Arkansas. It is very striking that a species of such wide distri- 

 \ bution should not occur at all in the Atlantic States. 



Say's synonymy is not in the least doubtful; compare especially the 

 foot-note in Wiedemann (Auss. Zw., ii, p. 118), where he explains that 

 Syrphus transfugus, to which Say compares his 8. affinis, is transfugus 

 Fabricius, a synonym of pyrastri, specimens of which he had sent to 

 Say. I was wrong in connecting S. affinis with S. lapponicus in my paper 

 on Syrphus (p. 149). 



In this species, the eyes of the male have an area of large facets in the 

 upper and middle portion ; a structure which I have not observed in auy 



*The pubescence of the eyes is always easier to perceive in male than iii female 

 Syrphi ; in the latter, a very careful examination is often required. 



