POLYGASTER. 139 
The following species characterized by M. Bigot, and referred by him to the genus 
Viviana, Rond. (one of them, however, with doubt), are perhaps best placed here :— 
Viviana (2) rufopygata, Bigot, Aun. Soc. Ent. Fr. 1888, p. 262. n. 46.—Mexico. 
citrina, Bigot, 1. c. n. 47.—Mexico. 
I may state that the genus Viviana, Rond. (Dipt. Ital. Prodr. iv. pp. 48 & 53), is closely 
allied to Myobia, and that its species have no discal macrochete on the abdominal 
segments and the antenne inserted above the median line of the eyes. 
POLYGASTER, gen. nov. * 
Head hemispherical, broader than the thorax; front a little prominent, as broad as the eyes ; frontal bristles 
robust, not descending beneath the root of the antenne; face slightly retracted ; two strong vibrissw 
inserted at the oral margin, these directed downwards, the oral margin not prominent. Antenne as 
long as the face; basal joints short; third joint four times as long as the second, somewhat convex on 
the front side; arista pubescent. Proboscis exserted; palpi filiform. Thorax elongate-quadrangular ; 
scutellum with two strong macrochete on the hind margin. Abdomen cylindrical, narrower towards 
the anus; the first and the anal segments shorter than the second or third, the latter each bearing a pair 
of marginal (but no discal) macrochete ; anal segment with macrochetw only on the underside. Legs 
rather elongate. Wings as long as the abdomen, without a costal spine; first and third veins short- 
haired over nearly their whole length ; curvation of the fourth vein angular, but without appendage ; 
apical cell opened at the wing’s tip; posterior cross-vein perpendicular, beyond the middle between the 
small cross-vein and the curvation of the fourth vein. 
1. Polygaster egregia, sp.n., 2. (Tab. IV. figg. 3; 34, head in profile.) 
Shining black ; first and second abdominal segments yellow and transparent, with a black dorsal band ; head 
and reflections on the thorax and abdomen white ; wings brownish, more intensely so towards the costa. 
Length 8 millim. 
Head white, somewhat silvery ; frontal band black, as broad as the lateral portions. Antenne black ; arista 
thickened nearly to the middle. Proboscis black ; the terminal lips and the palpi pale rufous. Thorax 
shining black, anteriorly and at the sides with a snow-white tomentum, and with two longitudinal black 
bands, between which (anteriorly) are two black lines; scutellum black. First and second segments 
yellowish and transparent, the first black at the base and each with a black dorsal stripe, which is 
slightly enlarged at the hind margin of the second segment ; the two hinder segments shining black, each 
with a trigonal white spot at the side. Legs black, the cox with whitish tomentum ; the tarsi pro- 
portionately thin; bristles weak ; foot-claws and pulvilli short. Tegule white. Wings brownish, darker 
along the costa, especially between the end of the auxiliary and the second veins; first and third veins 
with a row of short bristles, reaching to beyond the small cross-vein, the latter on the middle of the 
discal cell; curvation of the fourth vein with a blunt angle; apical cell rather narrow; posterior cross- 
vein nearly straight. 
Hab. Mexico, Teapa in Tabasco (H. H. Smith). 
A single female specimen. 
* sodvs (long), yaorjp (abdomen). 
t 2 
“ena 
