236 . DIPTERA. 
Hab. Mexico, Acapulco, Amula, and Dos Arroyos, all in Guerrero (H. ‘H. Smith), 
Santiago Iscuintla in Jalisco (Schumann), Northern Yucatan (Gaumer). 
Five male and three female specimens. 
20. Rhynchodexia imitatrix, sp.n., ¢ ¢. 
Blackish ; thorax grey, with obsolete black stripes ; abdomen laterally with whitish reflections; palpi and base 
of the antennex rufous ; legs black, the tibiee rufo-piceous. 
Length 7°5-8°5 millim. 
Closely allied to R. omissa, and, except for the blacker coloration and smaller size, difficult to distinguish 
from it. Owing to the more obscure ground-colour, the thoracic stripes are not so conspicuous ; in most 
of the male specimens the whitish-grey reflections on the abdomen are more extended, in such a manner 
that on each of the second and third segments a large ill-defined dark spot becomes conspicuous, the 
macrocheetee being inserted on this spot. The antenns are somewhat longer, especially their third joint. 
Hab. Muxico, Acapulco, Omilteme 8000 feet, Sierra de las Aguas Escondidas 9500 
feet, all in Guerrero, Teapa in Tabasco (H. H. Smith), Jalisco (Schumann). 
Several male and two female specimens. 
Notwithstanding its resemblance to R. omissa, I regard KR. imitatriv asa distinct 
species; moreover, the examples of this latter were captured (with a single exception) 
in other localities. Both species are allied to R. angulata (no. 14), but differ from it 
by the rounded curvature of the fourth vein. 
Bigot has likewise described the following species from Mexico :— 
Rhamphinina dubia, Bigot, Bull. Soc. Ent. Fr. 1885, p. xi. 
I have not seen the typical example of this insect, but it may perhaps belong to one 
of the above-mentioned species of Rhynchodewia. 
MYOCERA. 
Myocera, Robineau- Desvoidy, Essai sur les Myodaires, p. 328 (1830). 
Front of the male narrowed behind, that of the female broader than the eyes; face perpendicular, concave, 
carinated; oral margin prominent; vibrissal swellings slightly convergent, nearly parallel; vibrisss 
inserted at some distance above the oral margin; eyes bare; cheeks broad, their lower portion half as 
long as the longitudinal diameter of the eyes. Antenne inserted on a line drawn through the centre of 
the eyes ; third joint longer than the second ; arista plumose. Proboscis a little longer than the head ; palpi 
cylindrical. Abdomen conical (¢) or ovate ( 2), convex, with marginal, but without discal, macrochete. 
Legs of the male much longer than those of the female; in both sexes the tarsi longer than the tibie ; 
the tibie with scattered bristles ; foot-claws and pulvilli elongate in the male. Wings longer than the 
abdomen ; apical cell opened at a short distance before the wing’s tip; curvature of the fourth vein with 
a blunt angle; posterior cross-vein beyond the middle between the small cross-vein and the curvature of 
the fourth vein. 
