OSTEN SACKEN ON WESTERN DIPTERA. 325 



Front not unusually projectiug ; no conspicuous area of larger facets 

 in the middle of the eye of tbe 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; eyes pubes- 

 cent;* 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., ^. 

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

 eyes glabrous : 

 The second and third cross-bauds 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., i . 



Face and cheeks altogether yellow ; abdominal cross-bands 



rather narrow 5. opinator n. sp., ^ 9 - 



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. protritusn. sp., <?. 



1. &YUVB.VS PYRABTUi {Syrphus p2jrastri Lmn€, Fauna, Suecica; Sy?'- 

 plms transfugus Fabricius, Ent. Syst., iv, 306; Syrplms affinis Say, 

 Jouru. 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 

 Monica, February 18 ; Petaluma, April 28 ; San Eafael, May 29 ; Yo- 

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

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

 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 

 Syjphus transfugus, to which Say compares his iS. affinis, is transfugus 

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

 Say. I was wrong in connecting 8. affinis with 8. 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 midflle portion ; a structure which I have not observed in any 



* The pubesceuce'of the eyes is always easier to perceive iu male thau iu female 

 Syr2)hi ; in the latter, a very careful examination is often required. 



