E. T. CRESSOX, JR. 55 



ATISSIELLA new genus 



Similar to Atissa, as based on its type species Ephijdra pyg- 

 maea Haliday, but very distinct in the structure of the face and 

 in the arrangement of the facial bristles. 



Face conically prominent, but epistoma retreating; the prominence bearing 

 a pair of stout up curved bristles. There is also a series of two or more down 

 curved bristles below, and a series of dorso-laterally curved hairs along the 

 orbital groove. ^\'ings long, over-reaching the abdomen. Second vein short, 

 so that the third costal section is much longer than the second. Third vein 

 ending in the costa at the pointed apex of the wing. 



Genotype: Atissiella setulosa new species. 



Atissiella setulosa new species PI. Ill, fig. 9. 



Black, more or less brown pruinose, slightly shining except the head. Third 

 antennal joint sometimes yellowish below, basally. Halteres yellow. Basal 

 segment of hind tarsi yellowish. Wings immaculate, obscure hyaline. 



Mesonotum with a transverse series of six bristles just behind the sutural 

 region. Fifth abdominal segment of male pointed, triangular. Length. — 

 1 mm. 



Typc—d", Cartago, Costa Rica. July 4, 1909, [A. N. S. Type 

 No. 6128]. Paratypes.~l &,l 9 , Cartago, December 12, 1909, 

 (sweeping over mud); 1 cT, Juan Vinas, 2600 ft. alt., April 28, 

 1910, (at brook near woods). 



DISCOCERINA 



1835. Macquart, Hist. Nat., Dipt., ii, 527. 



1844. Stenhammar, Hand. K. Sven. Vet. Akad., 251 {Clasiopa). 



AlHed to Psilopu. The structure of the face and the form of 

 the third antennal joint are the best characters for separating the 

 two genera. In this genus the former is usually deeply l)ifoveo- 

 lated above, in profile prominent medianly, then evenly retreat- 

 ing to the epistoma, with a scries of two or mon^ up-curved, more 

 or less converging bristles each side. Antennae short, third 

 joint hardly ever longer than broad, usually not larger than second ; 

 spine of second usually minute. However, most of the species 

 may be distinguished by the opaque, pruinose thorax and irregu- 

 larh' arranged acrostichal setulae. In Psilopa the species are 

 more shining; facial foveae weak if developed, face not trans- 

 versely prominent medianly, antl the bi-istles limited to one on 

 each side. 



TRANS. AM. ENT. SOC, XLIV. 



