_Male._ Black, slender, shining. Head tawny, with two elongated piceous spots on the vertex; antennae tawny, third joint linear, rather long, arista bare; abdomen nearly fusiform, testaceous at the base; legs testaceous; wings limpid, with a blackish oblique streak extending from the base, with three blackish bands, and with a blackish costal streak extending round the tip, first and third bands slender, second broad, abbreviated like the first hindward; discal transverse vein straight, parted by about one-fourth of its length from the border, and by less than its length from the praebrachial transverse; halteres testaceous. Length of the body 1-1/2 line; of the wings 3 lines. 145. TRYPETA IMPLETA, n. s. _Foem._ Cinerea; capite albido; antennarum articulo tertio albido apice nigro; thorace vitta fusca, scutello albido, abdomine nigro; pedibus albidis nigro fasciatis; alis albis, maculis plurimis nigricantibus ex parte confluentibus; halteribus albidis. _Female._ Cinereous. Head whitish; third joint of the antennae short, conical, whitish, blackish at the tip, arista plumose; thorax with a brown stripe; scutellum whitish; abdomen black; legs whitish, with black bands; wings white, with many blackish spots, some of them confluent; discal transverse vein straight, parted by much less than its length from the border, and by a little less than its length from the praebrachial transverse; halteres whitish. Length of the body 1-1/2 line; of the wings 3 lines. 146. TRYPETA SUBOCELLIFERA, n. s. _Mas._ Cana; antennis albidis; thorace guttis fuscis, scutelli margine albido; abdomine fusco apicem versus cano maculis fuscis; pedibus albidis fusco fasciatis; alis limpidis, maculis nigricantibus pallido signatis ex parte confluentibus. _Male._ Hoary. Antennae whitish, third joint short, conical, arista plumose; thorax with some slight brown dots; scutellum brown, hind borders of the scutellum white; abdomen brown, hind borders of the segments and apical part cinereous, the latter with brown dots; legs whitish, with brown bands; wings limpid, with several blackish dots containing pale marks, some of them confluent and forming a middle band; discal transverse vein straight, enclosed in a pale streak, parted by much less than its length from the border and by much more than its length from the praebrachial transverse; halteres whitish. Length of the body 1-1/2 line; of the wings 3 lines. Subfam. ACHIIDES, _Walk._ Gen. ACHIAS, _Fabr._ 147. ACHIAS LONGIVIDENS, n. s. _Mas et Foem._ Viridi-cinerea; capite testaceo fasciis duabus vittisque tribus anticis nigris; antennis nigris; thorace vittis quatuor purpureo-nigris, pectore ferrugineo; abdomine viridi-fulvo; pedibus piceis; alis limpidis, costa lurido-nigricante, vena transversa discali fusco nebulosa; halteribus testaceis apice nigris. _Mas._ Oculis longissime petiolatis, scutello viridi, femoribus basi fulvis. _Foem._ Oculis subpetiolatis, scutello nigro-purpureo.