176 PSYCHE [Oct.— Dec. 



Hudson_;Bay Territory, Fort Resolution, (Kennicolt.) (') ; Colorado, (Hough 

 collection, C. F. Baker). 



Profile of head of male and female figured on plate. 



3. Nemotelus unicolor Loew. 



Nemotelus loiicolor Loew. Cent., iii, 11. (O 



Williston, Can. ent., 1S85, p. 128. (2) 



Williston, Biologia Centr.-Amer., Siippl. p. 251. (3) 



Nemotelus nigrinus Fallen, v. d. Wulp, Tijdschr. entom., 1867, p. 126. (4) 



Female. Bare, shining, black, antennae concolorous, front immaculate, a very slender 

 lateral line on the thorax yellowish, femora black except the yellowish tip, anterior tibiae 

 subfuscous, hind ones black, the base and extreme apex of all yellowish. Length of body 

 i| lines (3.5 mm.), length of wing if lines (3.3 mm.). 



Bare, shining, black. Front immaculate. Antennae black. Face produced into a rather 

 large and sharp cone. Lateral line of the thorax pale yellow, very thin. The hind tibiae 

 and the femora black, the tip of the latter and the base and apex of the former yellowish ; 

 anterior tibiae subfuscous, with the base broadly and apex narrowly yellowish, sometimes 

 wholly pale yellowish ; the last two joints of the yellowish tarsi sometimes infuscated. 

 Halteres whitish. Wings whitish, the stronger veins very pale yellowish. [Translation.^ 



Illinois, (Le Baron) (') ; Wisconsin (■♦) ; Pennsylvania, Arizona (-); Tabasco, 

 Mexico. (3) 



The male which has not been described before is similar to the female. The 

 outline of the head is naturally different as represented on the plate. The thorax 

 is sometimes decidedly pubescent with very fine whitish hair. Halteres often 

 blackened. 



Profile of head of male and female figured on plate. 



This is the commonest species in Illinois : Chicago, Glen Ellyn, Algonquin, 

 McHenry are the localities from which I have specimens. May to September. 

 One female from Glen Ellyn has the facial prominence shorter than the head, the 

 antennae reddish beneath and the knob of the halteres blackish. All the other 

 females examined have a longer face, black antennae, and white halteres. Is not 

 N. unicolor the form referred by van der Wulp to /ligrinus Falle'n ? The descrip- 

 tions of the European species apply very well to the North American specimens. 



A single specimen in the Hough collection taken in Hayti seems closely related 

 to iV. unicolor. Were it not for the extended distribution of this species and the 

 fact that the Glen Ellyn specimen of unicolor represents a similar variation, the 

 West Indian example might be considered another species. Its peculiarities are 

 the following: thorax with a black bronzed tinge; antennae brownish basally ; 

 face short, in length less than the width of the eye; length 2.25 mm. See figure. 

 The specimen scarcely seems to be the female of any of the three species occurring 

 within its geographical range. {IV. immciculafus, slossonac, Jlavicornis.) 



