192 PROCEEDINGS OF THE ACADEMY OF ' [Oct., 



In the study of some North American material in conjunction with 

 typical vibrans from Europe, I have made some notes on the genus 

 and the species included, and have found a new form which seems 

 to belong here. The form found within our fauna has been listed 

 in the catalogues and placed in collections as colon Lw., and some- 

 times as vibrans Linn. For some time I have been endeavoring to 

 separate these by means of the descriptions, notes given by Loew, 

 and examination of material, but with no degree of satisfaction. 

 A critical study of a specimen of vibrans from Europe has given the 

 same result, and so it is ev^ident to me that colon and vibrans are 

 synonymous. The examination of the types of these two species 

 may give contradictory results. 



Seioptera vibrans Linn. 



1761. Musca vibrans Linnaeus, Faun Suec, 1867. 



1867. Se'optera colon Loew, Berl. Ent. Zeit., xi, 296, (Cent., ii, 6). 



In this species we have the frons one-third to one-fourth width 

 of head, opaque, red orange, not with conspicuous silvery orbits; 

 median orange portion black setulose. Face slightly lighter, more 

 yellowish, in profile nearly straight on account of the prominent, 

 obtuse keel; orbits silvery. Cheeks concolorous. Occiput, thorax 

 and abdomen, shining black. Legs black but tarsi brown, especially 

 basally. No supraalar bristles. Mesopleura with pale micro -pubes- 

 cence; sternopleura with 1-2 bristles well separated. Ovipositor 

 with basal segment narrow, much narrower than long. Wings 

 hyahne with stigma and spot at apical margin infuscated. First 

 posterior cell narrowed so that its apex is no broader than its base. 

 Anal cell with slight point at apex. 



The specimens from our fauna, with one or two exceptions, seem 

 to have only one sternopleural bristle. These bristles are so slender 

 and hair-like that they are probably variable. Seventeen male and 

 six females have been examined from Canada, Rhode Island, New 

 York, Pennsylvania, Illinois, and Montana. 



Seioptera albipes new species. 



Here we have a species offering a different facial profile from 

 that of vibrans, being distinctly concaved with a weak carina. The 

 frons is broader than in that species, with shining orbits which are 

 only very narrowly silvery. There is a distinct supraalar bristle 

 and the mesopleura are black, setulose or pubescent; sternopleura 

 with two hair-like bristles close together. The fore tibiffi and tarsi, 



