from the Bio Xautia, State of Vera Cruz. 25 



description, but differing in the very constant character of 

 the median abdominal vitta. Fac3 wholly silvery; the 

 anterior half (or more than one third) of the front rafou3 

 yellow, with the silvery of face extending narrowly on sides 

 of this yellow portion and ending in a point on each side. 

 Kest of front soft opaque black, except the shining black 

 oc ellar area. First antennal joint light yellow, as is base of 

 sec ond ; rest of antennte rufous, the third joint being more or 

 less tinged with fuscous on upper edge and tip ; arista 

 blackish. Second antennal joint in all the specimens fally 

 as long as third, or even sometimes appearing very slightly 

 longer; base of third joint about same width as apex of 

 second. Proboscis of ordinary length for the genus, each 

 of the two joints about 3 millim. long, broadly whitish on 

 tip, yellowish at base, with more or less of a silvery-white 

 reflection. Mesoscutum blackish, with humeri and broad 

 lateral borders yellow (in one specimen darker at base of 

 wings), the yellow also continuing around hind margin and 

 extending anteriorly in a median pair of short vittaj nearly 

 to transverse suture, each vitta terminating in a point, which 

 is connected by a usually distinct line with the yellow of the 

 humeri. The suture is also marked, especially on lateral 

 sections, with a faint yellow line. In fact the thorax might 

 be described as yellow, with three heavy closely approxi- 

 mated black vitt£B on dorsum ; the middle vitta widest, 

 beginning on extreme front border of thorax and ending in 

 a point (sometimes faint) at scutellum ; the lateral vittss 

 strongly abbreviated in front, their outer borders convex, 

 and ending rather pointedly behind at scutellum. Sides of 

 thorax silvery pollinose, with a faint or nearly obsolete touch 

 of brownish below and a little before wing-bases, the brownish 

 with shining surface. Scutellum pale yellowish, brownish 

 on disk. Abdomen yellowish; first segment more or less 

 brownish on dorsum, sometimes as a posterior margin, some- 

 times as a geminate marking indented on middle in front ; 

 second to fifth segments brown or blackish on posterior 

 margin, the fourth and fifth sometimes with a dark tinge on 

 anterior portion, and always more or less distinctly silvery- 

 white pollinose on all except the brown hind border ; a 

 distinct (in one female only is this indistinct) median brown 

 vitta on second to fifth segments, dilated into a triangle on 

 second segment, the base of the triangle being coincident 

 with front border of segment. Abdomen thinly clothed with 

 short black hairs. Ovipositor of female hardly as long as 

 abdomen, composed of two segments : first segment usually 

 longer than second including the appendages of latter, with 

 more or less brown or blackish on dorsum ; second segment 



