MORDELLISTENA. 319 
triangular, its inner and apical sides about equal in length in the male, unequal in the female; antenne 
_ testaceous, slender, elongate, subfiliform—( ¢ ) joint 3 short, 4 stouter than and twice as long as 3, 4-10 
elongate, subequal—( 2 ) joint 4 longer but very little stouter than 3, 5-10 subequal; prothorax trans- 
verse ; elytra elongate, very gradually narrowing from the base; beneath coloured as above, the breast 
sometimes infuscate; pygidium elongate, a little shorter in the female, twice the length of the hypo- 
pygium ; legs reddish-testaceous, the hind pair darker; the hind tibiz with five, the first joint of the 
hind tarsi with four, and the second joint with two, oblique, parallel ridges. 
Length to end of the elytra 33-4, to tip of the pygidium 44-5, millim. ; breadth 13-14 millim. (¢ 9.) 
Hab. Guatemata, Cerro Zunil, Mirandilla, Panajachel (Champion). 
Six examples—one pair from each of the first-mentioned localities, two females from 
Panajachel; the description is made from the former. The two Panajachel females 
differ from the others of the same sex in having the third and fourth antennal joints 
subequal. A narrower and less robust species than MW. castaneicolor and its allies; the 
antenne elongated in the male and much more slender, the pygidium more slender. 
From WV. instabilis in all its varieties, some of which have the elytra very similarly 
marked, the more elongate shape and the long and slender antenne sufficiently 
distinguish it. 
16. Mordellistena opalescenticeps. (Tab. XIV. figg. 9, ¢; 9a, antenna.) 
Moderately elongate, rather robust, cuneiform, black, the head with a brilliant opalescent lustre; the head, 
the prothorax with the base and apex laterally, and the sides indeterminately, the scutellum, the elytra 
with a short oblique stripe extending from the shoulders inwards but not reaching the suture, a broad 
transverse fascia a little beyond the middle (not quite reaching the suture or lateral margin, slightly 
excised in front and behind, and widening a little outwardly), the suture narrowly thence to the base, 
and a large spot at the apex of each (not quite reaching the suture), and the base of the pygidium, 
yellowish-cinereous-pubescent, the rest of the pubescence brownish-black. Head somewhat flattened in 
the middle, obsoletely channelled in the centre behind; palpi (¢) testaceous, the last joint of the 
maxillary pair long and stout, scalene-triangular ; antenne ( ¢ ) piceous with the four basal joints reddish- 
testaceous, elongate, filiform, joint 3 slender, 4-11 stout, 4 twice as wide as and very much longer than 3, 
5-10 decreasing gradually in width, 7-10 very much longer than broad, 11 longer than 10; prothorax 
transverse ; elytra moderately long, gradually narrowing from the base; beneath black, the sides of the 
breast and the base of each ventral segment yellowish-cinereous-pubescent ; pygidium very elongate, 
rather stout, about two and a half times the length of the hypopygium ; anterior legs testaceous, the 
middle pair piceous, the hind pair black with the tibial spurs testaceous; the hind tibise with five 
(including the subapical one), the first joint of the hind tarsi with four, and the second joint with two, 
short, oblique, parallel ridges. 
Length to end of the elytra 34, to tip of the pygidium 43, millim.; breadth 1j millim. (¢.) 
Hab. Guatemata, Senahu in Vera Paz (Champion). 
One male example. Allied to UV. forticornis, from the same sex of which it may be 
easily distinguished by the much shorter antenne and longer pygidium, the flattened, 
opalescent head, and the stout and much more angular apical joint of the maxillary 
palpi. The fourth and fifth joints of the antenne are subequal; this character will 
distinguish 1. opalescenticeps from all the varieties of MW. instabilis (3), in which, 
however, these organs are paler in colour, shorter, and more slender. 
