THE CANADIAN ENTOMOLOGIST 323 



Gonomyia (Gonomyia) aequalis, sp.n. 



Male — Length 6.1 mm.; wing 6.6 mm. 



In all general features quite similar to Gonomyia mexicana, 

 the main differences lying in the genitalia of the male, these being 

 as follows: Ninth tergite almost straight across or slightly con- 

 cave; ninth pleurite moderately stout, the dorsal angle produced 

 caudad as a very slender, finger-like lobe, which is provided with 

 numerous setigerous tubercles; at the base of this lobe on the inner 

 side is a tiny, fieshy protuberence directed proximad; dorsal pleural 

 appendage irregular, fleshy, directed proximad, the caudal or 

 outer face near the apex with a strong, curved, chitinized hook, 

 which is directed dorsad and cephalad, the cephalic or inner face 

 with a row of strong bristles which are longer and more approxi- 

 mated at the tip; ventral pleural appendage a pale, fleshy lobe 

 densely covered with short, pale hairs; penis-guard rather long, 

 compressed, the median appendage pale, slightly curved; anal 

 tube broad, prominent, subtended on either side by a concave 

 wing that bears on the caudal outer angle a fimbriate tuft of yellow- 

 bristles. 



Habitat — Guatemala. 



Holotype — cf , Totonicopan, Guatemala; July, 1902; ((i. 

 Eisen) . 



Allotype — 9, topotypic. 



The types are in the United States National Museum. This 

 species was earlier determined as being a variety of Gonomyia 

 unicolor (Proceedings of the United States National Museum, 

 vol. 44, p. 507, 1913), but is readily separated from both unicolor 

 and mexicana by the structure of the male genitalia. \n(j. unicolor 

 the hypopygium may be described as follows: Ninth tergite almost 

 straight across or slightly concave; ninth pleurite moderately stout, 

 elongated, the dorsal angle not produced; dorsal pleural appendage 

 a subcylindrical, fleshy lobe from an enlarged base, at the apex, 

 with two powerful bristles, the cephalic or inner face with four 

 small hairs that are evenly spaced; ventral pleural appendage a 

 double lobe, dark-coloured, subchitinized, the inner arm stout, 

 cylindrical, with the tip acute, the inner side with two or three 

 hairs, the outer or more ventral arm is slender, curved, and bears 



