154 TRICHOPTERYGIDA. 
dentate. Wings pedunculate, long and narrow, fringed on both sides with long movable sete. Antenne 
long and slender, 11-jointed, with the two basal joints very large, the intermediate very long and very 
slender, and the last three forming a much incrassated moniliform club, ornamented with long verticillate 
hairs. Palpi: maxillary large, 4-jointed, with the third joint very large, ovate, not truncate; apical joint 
rather small, acicular, and sinuated ; labial short and robust, with the labial processes short, transverse, 
3-jointed, with the apical joint ovate. Prosternum very short; episterna small and narrow; epimera 
small and distinct, not enclosing the coxal cavities; coxal cavities large, contingent, open behind. 
Mesosternum moderate, elevated into a long carina, extending from the collum to beyond the coxal 
cavities; episterna small and narrow; epimera very large and broad, extending to the coxal cavities ; 
coxal cavities large and round, separated by the carina. Metasternwm large, transverse, extending to the 
sides of the body, and produced between the posterior coxe into an acute point; episterna covered for the 
most part by the elytra, but with their interior apical angles broadly inflexed below the mesosternum ; 
epumera concealed by the elytra, with their extremities only visible below the metasternum. Venter 
composed of seven segments, of which the last two are separately longer than either of the preceding 
segments; apical segment simple. Legs moderate; posterior coxe very large, and broadly laminated ; 
tibie setose, armed with long spurs; tarsi 3-jointed, with the two basal joints large, the third very long 
and slender. 
Throscidiwm is distinguished from Nossidium by the more elongate form of the body, 
and the produced posterior angles of the thorax, as well as by the great dissimilarity 
of the whole underside of the external skeleton. Its Central-American exponent, 
T. invisibile, was described by Nietner as a species of Trichopteryx, and is quoted as 
such in the ‘Trichopterygia Illustrata;’ but from the examination of more recent 
captures I feel convinced that it belongs to the present genus. The two other known 
species are both from Chili. 
1. Throscidium invisibile. (Tab. III. fig. 25.) | 
Trichopteryx invisibilis, Nietner, Ann. & Mag. Nat. Hist. 2nd ser. xix. p.879'; Matth. Trich. Illustr. 
p- 121, t. 24. f.10°; Cist. Ent. iii. p. 45°. 
Acrotrichis invisibilis, Wollast. Col. Hesperid. p. 54‘. 
Throscidium invisibile, Matth. Trans. Am. Ent. Soc. xi. p. 154°. 
Acratrichis elongatula, Motsch. Bull. Mosc. xli. part 2, p. 180°. 
Elongate oval, moderately convex, translucent livid-castaneous, rather thickly clothed with short sericeous 
hair; head large and prominent; eyes small and prominent; thorax moderate, slightly dilated posteriorly, 
ornamented with minute tubercles arranged in rows, straight on the disc but curved at the sides, with the 
interstices faintly reticulated, and also with a smooth and shining space at the base, the basal margin slightly 
sinuated, with the angles nearly rectangular; elytra long, not broader than but half as long again as the 
head and thorax, rather deeply and reticulately asperate; abdomen with the pygidium only exposed; 
legs and antennz pale yellow, the former long and robust, with the basal joints of all the tarsi incrassated. 
Length 54 lin.=0-50 millim. 
Hab. Guaremata’, San Gerénimo (Champion *); Isrumus of Panama (Mots- 
chulsky * ® °).—Cryton! 2%; Cape VERDE IsLanps 2? 4, 
This species, found by Mr. Champion near San Gerénimo, Guatemala, appears to be 
widely distributed in the tropical zone; it was first discovered by Nietner in Ceylon, and 
subsequently found by Wollaston in the Cape Verde Islands and by Colonel Motschulsky 
near Panama; the last-named illustrious entomologist describing it under the name of 
Acratrichis elongatula. 
