ORTALID^E — TRITOXA. 105 



only moderately narrow hyaline bands, the second and third of which 

 are arcuated ; the latter is less remote from the apex of the wing than 

 in the other species ; posterior crossvein oblique. Long. corp. 0.25 — 

 0.3 ; long. al. 0.22—0.26. 



Reddish, chestnut -brown, with a black abdomen. Front 

 opaque, with the exception of the edge of the vertex and of the 

 small callosities descending from it, and bearing the bristles ; 

 along the orbits the front has a narrow border of white pollen, 

 which also extends over the face, but is much broader here. The 

 remainder of the face has a very thin, somewhat yellowish 

 pollen upon it, which is most perceptible in the proximity of the 

 antennae. Antennae reddish - brown ; third joint darker brown 

 towards its end ; pubescence of the arista short, but distinct. 

 The thoracic dorsum has a broad shining border upon its sides, 

 otherwise it is opaque. Its thin whitish pollen is a little more 

 perceptible than in T. flexa, and forms, as in that species, two 

 broad, parallel longitudinal stripes, the position of which corre- 

 sponds to that of the intervals between the ordinary thoracic 

 stripes ; upon the intermediate stripe between them the pollen 

 has a somewhat yellowish tinge, and is much more dense upon 

 the longitudinal line, which divides this stripe in two ; well- 

 preserved specimens show the white pollen on the sides of the 

 thoracic dorsum also, while in less good specimens this is not 

 visible, and often very little of the pollen is left on the whole 

 surface. Scutellum, metanotum, and pleurae are shining, the 

 latter with a thin white bloom. Abdomen black or brownish - 

 black, with a black pubescence, sometimes chestnut-brown on the 

 sides of the first and second segments. The flattened first joint 

 of the ovipositor is of the same nature as the preceding seg- 

 ments of the abdomen ; it is very broadly truncated at the tip. 

 The feet have the same coloring as the thorax, often, however, 

 not only the upper side of the fore femora, the middle femora 

 towards their basis, and the hind femora, with the exception of 

 their last quarter, are more strongly infuscated, but also the fore 

 tibiae towards their tip, as well as the entire fore tarsi ; the middle 

 tarsi, with the exception of their basis and the entire hind tibiae 

 and hind tarsi, are dark brown. Halteres yellowish. Wings 

 narrowed towards the basis, although not quite as cuneiform as 

 in T. flexa, the portion lying beyond the sixth longitudinal vein 

 not being quite as narrow as in that species ; the end of the wing 



