50 A REVISION OF THE NEARCTIC SCIOMYZIDAE 



c?', 9- Black, more or less grayish; head, antennae, except apices of third 

 joint, palpi, humeri, apex of scutellum, apex of abdominal segments and legs, 

 except fore tibiae and tarsi, paler. Frontal orbits narrowly silvery; median 

 stripe narrow, hardly attaining anterior margin ; orbital spot of face indistinct 

 or absent. Mesonotum narrowly striped. Median stripe of abdomen brown. 

 Wings clear. Length.— 3 to 4.5 mm. 



The synonymy of humilis is by Hendel (1902, p. 66). 



Of this species I have examined : 3 9 and 5 cf • 



Pennsylvania: Swarthmore, September, (E. T. Cresson, Jr.), [A. N. 

 S. P.]. 



Florida: St. Augustine, March 15, [Johnson]. 



California: Los Angeles, May 1, (M. C. VanDuzee), [VanDuzee]. San 

 Diego County, April 17, (M. C. VanDuzee; desert edge), [VanDuzee]. 



Texas: Piano, October, (E. S. Tucker), [U. S. N. M.]. 



Melina (Ditaenia) trivittata new species 



Similar to grisescens but larger (5.5 to 6 mm.). Antennae entirely tawny; 

 silvery frontal orbits broader; facial orbital spot distinct and black; meso- 

 notal stripe broader and the abdomen with median and lateral series of nar- 

 row, brown spots. Wings yellowish with cross-veins clouded. 



Type. — 9 ; Fremont, Nebraska, August, 1900, [Cornell Uni- 

 versity Coll.]. 



Subfamily Euthycerinae 



This is Hendel's Tetanocerinae, but that name is not available 

 now. Hendel's characterization of this group is the reverse of 

 his Sciomyzinae. The prothoracic bristle is absent, while the me- 

 dian frontal channel is generally present. Further we may add 

 that the second antennal joint is generally quadrate or longer, 

 broad at base (exception is found in Sepedon). The genera may 

 further be associated into convenient groups which are here 

 designated as tribes, and may be characterized as follows: 



Arista black Chaetomacerini 



Arista white, or at most dark basally. 



Scutellum with four bristles Euthycerini 



Scutellum with only two bristles Sepedontini 



Tribe Chaetoinacerini 



Here we have all the characters of the subfamily, with the 

 addition of the black arista. This arista may be bare or plumose, 

 but is always black, at most only the extreme base pale. The 

 second antennal joint is generally quadrate, but becomes some- 

 what longer in some species. It is however more typically de- 

 veloped in the next tribe. 



