462 HETEROMERA. 
LYSTRONYCHUS. 
Lystronichus, Uatreille, Régne anim. 2nd edit. v. p. 41 (1829). 
Lystronychus, Lacordaire, Gen. Col. v. p. 514 (1859). 
Xystronia, Solier, Ann. Soc. Ent. Fr. iv. p. 238 (1835). 
About twelve species of this genus have been described, though many others exist 
in collections. The three species here enumerated each have the antenne of a 
somewhat different structure; they agree, however, well enough in other respects. 
Lystronychus is chiefly confined to Tropical America; two species are known to me 
from Texas, and Prostenus californicus, Horn, doubtless belongs to it. JZ. scapularis 
somewhat approaches Prostenus in the structure of the antenne, but differs in the 
non-clavate femora. 
1. Antenne very long, slender, and filiform ; upper surface unicolorous, opaque. 
1. Lystronychus piliferus. (Tab. XXI. fig. 7.) 
Oblong ovate, feebly convex, obscure reddish-brown, opaque, above usually of a pruinose bluish-violet, obscure 
purplish, or greenish-bronzy tint, the surface somewhat thickly clothed with long erect hairs, and also 
sparsely pubescent. Head closely and coarsely punctured ; eyes rather large; antenne filiform, very long 
and slender, in the male reaching far beyond the middle of the elytra, joints 3 and 4 long, about equal, 
5-11 increasing a little in length, varying in colour from ferruginous to piceous; prothorax not much 
broader than long, the sides dilated at the middle, constricted behind, and rounded and a little more 
narrowed in front, the hind angles somewhat prominent, the base subtruncate (or very slightly rounded) 
and very feebly margined, the basal foves indistinct or obsolete, the disc unimpressed, the surface finely and 
very densely punctured; scutellum closely and finely punctured; elytra moderately long, with rows of 
very minute punctures placed upon obsolete strive, the interstices flat and each with a row of scattered 
coarser punctures, the punctures bearing long erect hairs; beneath more shining, the ventral surface some- 
what closely and finely, the metasternum sparsely and more coarsely, punctured; legs long and slender, 
clothed with short bristly hairs, piceous or ferruginous, the basal half of the femora often testaceous, the 
femora not swollen towards the apex, the basal joint of the hind tarsi long. 
Length 6-83 millim.; breadth 2-3} millim. (¢ 2.) 
Hab. Norta America, Texas (coll. Dr. Horn).—Mexico (coll. F. Bates), Matamoros 
Izucar, Colima city, Oaxaca, Tapachula in Chiapas (/Hége), Tepansacualco, Cordova 
(Sailé) ; Guatemaua, San Juan in Vera Paz, Tocoy, El Jicaro, San Geronimo (Champion), 
Chinautla (Salvin); Nicaragua, Chontales (Belt, Janson).—CotomsBiA, Bogota; BraziL. 
A widely distributed and not uncommon species in Central America, extending 
northwards to Texas and southwards to Brazil. An example from Mexico in Mr. F. 
Bates’s collection from that of Dejean is labelled “ Gen. nov. piliferum,” and another 
from Colombia “ geniculatus, Reiche.” This insect bears a rather different facies to 
the typical Lystronychi, L. equestris, L. pulchellus, &c., on account of the still longer 
and more filiform antenne, larger eyes, and more depressed form. ‘The basal half 
of the femora is frequently testaceous, about half the large number of specimens 
before me being thus coloured. Dark-coloured individuals have the upper surface of 
