PHOROCERA.—TRIXA. 87 
‘Mz. Bigot has characterized three species of the genus Phorocera from Mexico; but 
I cannot recognize in them any of the species here described. 
_ Phorocera barbata, Bigot, Ann. Soc. Ent. Fr. 1888, p. 260. no. 36.—Mexico. 
melanoceps, Bigot, loc. cit. no. 37.—Mexico. 
parva, Bigot, loc. cit. no. 38.—Mexico. 
TRIXA. 
Triza, Meigen, Syst. Beschr. europ. Zweifl. Ins. iv. p. 222. no. 147 (1824). 
Of this well-defined genus, one species only, 7. wncana (Fabr.), was hitherto known 
from America; in the collections sent by Mr. H. H. Smith from Mexico I find two 
others, which are described below. 
The genus is especially characterized by the head being distinctly prolonged beneath 
the eyes; the antenne are very short and rest in a deep groove of the face, nearly in 
the same manner as in the CEéstride; above the oral margin there are some bristles, 
these mounting on the facial ridges to half the length of the face, and among which 
the vibrissee do not show a greater development. The Mexican species agree in their 
general facies with the European forms; only the front is more prominent and the 
face somewhat inclined ; the palpi are less thickened ; the abdominal segments have 
no discal macrochete ; and the wings have a small costal spine. These differences, 
however, are not sufficient to justify a generic separation, when all other characters are 
present. 
The two species may be easily recognized by the following differences :— 
Abdomen rufous (¢) or blackish (¢), with grey and white reflecting 
spots . . .. . obsoleta, v. d. Wulp. 
Abdomen without whitish or grey reflecting spots, rufous with a black 
dorsal stripe (¢), or black with some white reflections only on the 
analsegment(?). . . . 2... ee e ws ee es s) differens, v. d. Wulp. 
1. Trixa obsoleta, sp.n., ¢ 2. 
Thorax and scutellum blackish ; abdomen black with whitish reflecting spots, in the male laterally rufous ; 
head and basal joints of the antennz rufous; legs black. 
Length 8-11 millim. 
Front prominent and forming almost a right angle with the face—in the male much narrowed behind, 
laterally cinereous, and with a rufous median band; in the femaie broader than the eyes, yellowish- 
cinereous, the median band blackish, sometimes inconspicuous. Frontal bristles on both sides in a single 
row, in the female less numerous, but more robust. Face and cheeks rufous, with grey or yellowish 
reflections, the face with a deep median groove, the cheeks with a trigonal impression under the eyes. 
Basal joints of the antenne rufous, the second joint convex ; third joint black, as long as the second ; 
arista thickened in its proximal half. Proboscis black ; palpi small, pale rufous, the tip slightly thickened, 
black, and beset with black hairs. Thorax and scutellum black, with some greyish or cinereous tomentum, 
which in the female is more conspicuous and interrupted on the thoracic dorsum by four black stripes. 
Abdomen ovate; first segment black; the following segments black with whitish reflections—in the male 
broadly rufous at the sides and somewhat transparent, in the female with the anus only rufous; macro- 
