MORDELLISTEN A. 37 
sexes. The palpi and pygidium are similarly formed in the male and female. The 
Guatemalan specimens have their under surface darker in colour than those from 
Mexico, and one of them has a well-defined dark vitta on the disc of the thorax ; these 
examples also have the opalescent. lustre on the head much more distinct. The ground- 
colour of the elytra is apparently dull piceous or black, but when the pubescence is 
removed the surface is shining and has a metallic violaceous lustre. I. hexastigma is 
very similar in colour, but it has differently formed palpi and antennz and a shorter 
pygidium. 
12. Mordellistena crassipyga. (Tab. XIV. fige. 5; 5a, antenna; 54, hind 
leg.) 
Elongate, robust, rather broad, cuneiform, black; the head, the prothorax in front and at the base, the 
scutellum, the elytra with the extreme base, a large oblique postmedian spot on the disc, the suture very 
narrowly to about the middle, and the apices, yellowish-cinereous-pubescent, the rest of the pubescence 
on the elytra purplish-black, and that on the prothorax brown. Head moderately convex ; palpi reddish- 
testaceous, the last joint of the maxillary pair darker, the latter elongate, scalene-triangular, its outer 
side straight ; antenne long and filiform, pitchy-black with the four basal joints reddish-testaceous, 
joint 3 slender, 4-11 thickened, almost equal in width but slightly decreasing in length, 4 about twice 
the length and nearly twice the width of 3, the penultimate joints twice as long as broad; prothorax 
transverse ; elytra long, gradually narrowing from the base; beneath black, the sides of the breast and 
the extreme base of the first and second ventral segments with some yellowish-cinereous pubescence ; 
pygidium stout, broad at the base, conical, short, twice the length of the hypopygium; legs piceous, the 
anterior femora and the anterior and intermediate tibie partly testaceous, the hind tibial spurs testaceous ; 
the hind tibiee with six (including the subapical one), the first joint of the hind tarsi with five, and the 
second joint with two, short, oblique, parallel ridges. 
Length to end of the elytra 43, to tip of the pygidium 5, millim.; breadth 14 millim. 
Hab. Mexico, Chilpancingo in Guerrero (H. H. Smith). 
One example. Very close to M. forticornis, of which I at first supposed it to be 
the female. In the females of the allied I. sewmaculata (which has similarly formed 
antenn in the male) the fourth antennal joint is short and very little larger than the 
third; in MV. crassipyga the fourth and fifth joints are thickened, elongate, and equal 
(as in the male of M. forticornis), and to judge from analogy the specimen described is 
a male. It has the antenne much shorter and more slender than in M. forticornis ( 3); 
the elytra are without an oblique post-basal pubescent fascia; and the pygidium is 
much shorter and stouter. 
13. Mordellistena forticornis, (Tab. XIV. figg. 6,3; 6a, maxillary palpus.) 
Elongate, cuneiform, black ; the head, the prothorax at the sides and base, the scutellum, the elytra with the 
extreme base, an oblique stripe extending from the shoulders inwards but not quite reaching the suture, 
an oblique patch on the disc a little beyond the middle (widening inwardly and not reaching the suture), 
the apices, and the suture narrowly from the base nearly to the apex, yellowish-cinereous-pubescent, the 
rest of the pubescence on the elytra purplish-black and that on the prothorax brown. Head moderately 
convex ; palpi (¢ ) testaceous, the last joint of the maxillary pair very elongate, rather narrow, scalene- 
triangular; antenne (¢) pitchy-black with the three basal joints testaceous, very elongate, filiform, 
