Famity—SIRICID &. 121 
ORYSSUS AMAZONICUS. Westw. 
Prate XXII, Fie. 8. 
Niger, punctatissimus: capite duplici serie tuberculorum ; antennis nigris articulis 3-7 albidis ; pedibus 
piceis femoribus nigris; alis hyalinis fascia abbreviata ante, alteraque lata pone medium fuscis. 
Long. corp. lin. 34; expans. alar. antic. lin. 54. 
Habitat ; Amazonia (Bates). In Mus. Hopeiano Oxoniz. 
The head is rugose and granulated, with two rows of conical tubercles between the eyes (fig. 8a). The 
antenne have the third and four following joints buff, the fourth and sixth being longer than the fifth and 
seventh. The thorax is rugosely punctured, the abdomen more delicately, the basal jot having a transverse 
row of fine striole at its base, divided in the middle by a small polished tubercle, the remainder of the segment 
being more strongly punctured than the rest of the abdomen. The legs are robust and pitchy black, the 
extremity of the tibie and the tarsi being more pitehy. The wings are hyaline, the fore wings with an abbre- 
viated fascia before the middle of the wing, terminating in an oval spot in the middle of the dise; and beyond 
the middle of the wing is a broad brown fascia. The vein closing the first submarginal cell is colourless between 
the dark fasciz. 
Genus—DERECYRTA. 
(Smith, Ann. Nat. Hist. grd Ser. vol. vi. p. 255; Xéphydrina, Westw. MS.) 
Head subglobose, vertex swollen or convex ; eyes lateral, large, ovate ; ocelli prominent, placed in a triangle 
between the eyes; antenn# setaceous, composed of 23-26 joints, the scape short, curved, slightly thickened 
towards the apex; the first joint of the flagellum half the length of the scape, the second as long as the scape, 
third and four following joints as lone as the first, the remaining joints are each in succession shorter than the 
preceding. Thorax as wide as the head, oblong, the sides parallel; the prothorax narrowed anteriorly into 
a short neck; the mesothorax slightly elevated in front; the scutellum elevated; the metathorax with a deep 
incision in the middle; the anterior wings with one or two marginal and four submarginal cells, the marginal 
cell, or cells, elongated, with a short appendix at the apex ; the first submarginal cell small, the second oblong, 
widest at the apex, the third subquadrate, the fourth extending to the apex of the wing: the second and third 
cells each receive a recurrent vein a little within their base; legs slender, not compressed; the four hind 
tibie bispinose at their apex; ungues with a strong broad tooth at the base; abdomen cylindrical, about twice 
the length of the head and thorax; the ovipositor short, and slightly exserted. 
This genus is evidently identical with Brachyxiphus of Philippi (Stettiner Entom. Zeit. 32 Jahre. 1871, 
p- 285, pl. III), although there are several characters given by that author which differ from those which I 
have observed. The maxillary palpi are described as 6-jointed, the first four joints of equal length, and the last 
shorter. They are, however, figured as only 5-jointed, with the first to the fourth of equal length, and the fifth 
shorter and oval (see his fig. 14). The labial palpi are described as 4-jointed, the third joint the shortest and 
the last egg-shaped (see his fig. 1c). Of the sexes he observes—‘ Mannchen habe ich nicht gesehen.’ His 
figures of his two species evidently, however, represent both sexes, figure 1 being a female, and figure 2 a male. 
He also notices the difference in the number of marginal (radial) cells in the individuals constituting his two 
species, described as follows :— 
1. Brachyxiphus grandis Ph. (fig. 1), niger, abdominis seementis 3-8 aurantiacis; antennis 26-articulatis ; alis 
nigricantibus cellulis radialibus duabus. Long. corp. 104 lin.; exp. alar. 19 lin. Hab. Valdivia. 
2. Brachyxiphus flavipes Ph. (fig. 2), niger, pedibus flavis ; antennis 18-articulatis, in medio albis; alis nigrican- 
tibus, cellula radiali indivisa. Long. corp. fere 6 lin.; exp. alar. antic. lin. 9. Hab. Valdivia. 
From this deseription, and the accompanying figures, it would appear that the specimen represented in his 
fig. 2, having all the appearance of a male, has only one radial (or marginal) cell; whilst his fig. 1, represented 
with a short ovipositor, as a female, has two radial cells: thus differing from the specimens represented in 
my plates, in which the male has two radial cells and the female only one. In this uncertainty, I hesitate in 
uniting the male insect, from Chili, represented in my plate XXIII, fig. 1, having two radial cells, with 
Philippr’s female, fig. 1, from Valdivia, which has also two radial cells, although agreeing with it in colours. 
R 
