PLAGIA.—MASICERA. 103 
band rufous-grey, as broad as the whitish lateral portions; frontal bristles stout, inserted on black points, 
two of them beneath the root of the antenne ; vibrisse at some distance above the oral margin; eyes bare. 
Antenne descending nearly to the vibrisse ; basal joints rufous; third joint black, twice as long as the 
second; arista thickened nearly over its whole length, the penultimate joint somewhat distinct. Proboscis 
shining black, exserted and straight, the terminal lips scarcely thicker; palpi very small, pale rufous. 
Thorax cinereous, the black stripes linear and only conspicuous before the transverse suture; scutellum 
blackish-cinereous. Abdomen conical; second and following segments for more than half their length 
whitish on the front borders, and with rather short marginal macrochete; ventral surface blackish. 
Front tibie with short bristles; middle and hind tibie with long bristles. Tegule whitish. Wings 
greyish ; first and third veins bristly over nearly their whole length, fifth vein bristly only at the base ; 
fourth vein prolonged beyond the curvation ; small cross-vein distinctly beyond the middle of the discal 
cell; apical cross-vein oblique and very slightly concave; posterior cross-vein straight and at a much 
shorter distance from the small cross-vein than from the curvation of the fourth vein. 
Hab. Mexico, Tierra Colorada 2000 feet and Amula 6000 feet, both in Guerrero 
(H. H. Smith). 
Three female specimens. 
4, Plagia incognita, sp. n., 9. 
Black ; thorax cinereous, with four black stripes; second and following abdominal segments with grey front 
borders; palpi and basal joints of the antenne rufous; proboscis slender and straight ; posterior cross- 
vein in the middle between the small cross-vein and the curvation of the fourth vein, 
Length 10 millim. 
Allied to the preceding species, but differing in the position of the posterior cross-vein, which, moreover, is 
distinctly curved outwards. The apical cell ends at a considerable distance from the tip of the wings, 
which is’conspicuously rounded. The rufous coloration on the inferior portion of the head is more extended ; 
the cheeks have some short and weak hairs, of which I see no trace in P. rigidirostris. It is uncertain 
whether the arista is shaped as in that species (thickened to near the tip), the antennez of the unique 
specimen being broken (the entire third joint of the right antenna and the arista of the left are 
wanting). 
Hab. Mexico, Chilpancingo 4600 feet in | Guerrero UH. H. Smith). 
A single female specimen. 
MASICERA. 
Masicera, Macquart, Suites 4 Buffon, Diptéres, 11. p. 118 (1835). 
_ The characters on which Macquart established this genus form a striking example of 
uncertainty and elasticity. Therefore it is not. surprising that he included in it very 
heterogeneous species, as Tachina vertiginosa, Meig., with bristles on the facial ridges, 
and Tachina confinis, Meig., with hairy eyes, among others having no bristles on the 
face and the eyes bare. The genus, however, has since been restricted by Meigen 
(System. Beschr. europ. zweifliigl. Ins. vii. p. 178) and Schiner (Fauna austriaca, 
Dipt. i. p. 481) to the species having the eyes bare, the facial ridges without bristles, 
and the vibrisse inserted just on the oral margin. In this sense it is closely allied to 
