306 Mr. F. Walker's Characters of iindescribed Diptera 



thence to its tip, wliich is far in front of the tip of the wing ; 

 discal transverse vein hardly curved outward, parted by about its 

 length from the border, and by less tlian its length from the 

 flexure, of the praebrachial ; alulee whitish. 



This species differs inuch, in the structure of the third joint 

 of the antenna?, from the typical form of LydtUa. 



Length of the body o\ lines ; of the wings 6 lines. 



Mexico. 



Lydella ? ind'ita. 



Foem. — Nigra, gracilis, cylindrica, sub-setosa, capite albo, 



frontalibus atris antice latescentibus, facie valde obliqud, 



palpis gracillimis, antennis epistoma vix attingentibus, ar- 



ticulo 3" linear!, thorace cinereo vittis quatuor indistinctis 



nigris, abdornine cinereo sub-tessellato, pedibus longiusculis, 



alis nigricante cinereis basi et costd interiore pallide luteis, 



raargine postico sub-cinereo, vena preebrachiali angulum ob- 



tusum fingente, vena discali transversa sub-undulata, alulis 



albis magnis. 



Female. — Black, slender, cylindrical, slightly bristly : head 



white; frontalia deep black, widening much in front; face very 



oblique; facialia without bristles; epistoma slightly prominent; 



palpi very slender; antennae nearly reaching the epistoma; third 



joint linear, rounded at the tip, about thrice the length of the 



second ; arista slender, stout at the base, very much longer than ' 



the third joint ; thorax cinereous, with four indistinct black 



stripes; abdomen much longer than the thorax, slightly tessellated 



with cinereous, with some black spines in the disk and more 



towards the tip ; legs rather long ; wings blackiah grey, pale 



luteous at the base and along half of the costa, slightly greyish 



along the hind border; praebrachial vein forming an obtuse angle 



at its flexure, near which it is very slightly bent inward, and is 



thence straight to its tip, which is somewhat in front of the tip of 



the wing; discal transverse vein slightly undulating, parted by 



half its length from the border and by much more than half its 



length from the flexure of the praebrachial ; alulae white, large. 



Length of the body 5\ lines; of the wings 9 lines. 



Mexico. 



Genus Tachina, Fabr. 



Tachina despicienda. 

 Ciiierea, setosa, capite albo sub-depresso, frontalibus nigris, 

 antennis breviusculis, articulo 2° ferrugineo, abdomine fasciis 



