150 HETEROMERA. 
referred to it are from North America, Colombia, or the Antilles; but very many of 
those included in Ananca, by various authors undoubtedly belong to it. The last-named 
genus was not characterized by its authors: of the five species enumerated as belonging 
to. it, all of which are from Chili, one only is known to me, A. serville (Sol.), and this 
is not congeneric with the Central and North-American species of Oxacis; A. servillei 
agrees with Oxacis in the simple form of the mandibles (cf. Solier, in Gay’s Hist. fis. y 
polit. de Chile, Zool. v. Atlas, t, 21. fig. 4 bis d), but differs in its longer head and more 
depressed and more oblong eyes. The species here referred to Oxacis agree in having 
the mandibles entire at the apex *; the antenne 11-jointed, with the apical joint usually 
constricted or emarginate at or beyond the middle, in both sexes; the eyes coarsely 
granulated (except in O. dugesi), very widely separated, oblique, and not prominent, 
usually large, and, at most, feebly sinuate or emarginate on their inner edge; the last 
joint of the maxillary palpi varying from subcultriform to subtriangular; the thorax 
oblong-cordate, always narrower at the base than at the apex; the anterior tibie with 
two spurs; the tarsi (except in O. variegata) with the penultimate joint only spongy- 
tomentose beneath; the claws toothed or angularly dilated, or, usually, only feebly 
dilated, at the base; the fifth ventral segment unemarginate in both sexes. Of the 
ten species from North America included by Leconte and Horn in Ozacis, examples of 
seven of which are before me, two at least, O. notoxoides and O. thoracica (Fabr.), have 
bifid mandibles, and these do not belong to the genus as here understood ; the former 
is apparently referable to Ditylus and the latter to Copidita. Hypasclera, Kirsch, based 
upon three species from Colombia, is, no doubt, congeneric with Ovacis; and of the 
numerous species of Copzdita from the Antilles described by Mr. C. O. Waterhouse 
(cf. Trans. Ent. Soc. London, 1878, pp. 306-309) all but one, C. lateralis, probably 
belong to the same genus, these having, apparently, the mandibles entire at the apex. 
In two of the species from Central America the posterior femora are much thickened 
in the male; this character, however, as in @demera, is not of generic importance. 
Various species from North and Central America, chiefly those frequenting the sea- 
shore, have the claws toothed within at the base; but as there are numerous others 
with the claws angularly or subangularly dilated, and many in which the dilatation is 
very feeble, this character cannot be regarded as of generic value ; the two species from 
North America with toothed claws were supposed by Leconte to belong to Prodosca. 
‘Numerous species of Oxacis are found only on or near the sea-shore, others in inland 
localities. | | 
Posterior femora incrassate in the male; eyes coarsely granulated; last joint of 
the maxillary palpi subcultriform and with the apical side longer than 
the inner side; tarsi with the penultimate joint tomentose beneath ; 
claws angularly or feebly dilated at the base . . . . . . . + +. Species 1, 2, 
- ® This cannot always be accurately ascertained without opening them; the right mandible (as noticed by 
Leconte) has in some species a short tooth on the upper inner side, but distant from the apex. 
