118 HETEROMERA. 
much more coarsely granulated eyes; and they will probably have to be separated 
from Ditylus. 
* Head largely developed in both sexes, in some species enormously large in the male. 
1. Ditylus brachinoides. (Tab. V. fig. 21, 2.) 
Elongate, rather convex, finely pubescent, varying in colour from brownish-ochraceous to ferruginous, the head 
usually with a piceous patch in the middle below the eyes, the elytra often darker, and sometimes of a 
blackish-brown tint, the prothorax shining, the head subopaque, the elytra very opaque. Head densely 
and very finely punctured, with a smooth raised line on the vertex behind—in small males and in the female 
moderately dilated behind the eyes, and as wide as the prothorax, in fully-developed males enormously 
large, much wider than the prothorax, with the sides largely and obliquely dilated behind the eyes, and 
extending laterally far beyond them, and abruptly constricted behind, and the mandibles also greatly 
elongated,—the eyes black, quite small, and not prominent; antenne varying in colour from testaceous to 
fusco-ferruginous ; prothorax about as long as broad, the sides much rounded anteriorly and strongly 
constricted behind, the hind angles acute, very broadly transversely depressed in front, and deeply 
impressed in the middle before the base, the disc usually with a shallow depression on each side about 
the middle, the surface very minutely, closely, and irregularly punctured (more sparsely so than that of 
the head), a very narrow longitudinal space down the centre, raised in the middle or in front, and deeply 
impressed behind, impunctate, the apex emarginate in the middle in fully-developed males; elytra 
moderately long, a little convex, rather narrow at the base and widening to far beyond the middle, 
somewhat obtuse behind, very finely, closely, and shallowly punctured, with two rather broad vague coste 
down the middle of the disc and one near the sides, extending from the base nearly to the apex, the suture 
also a little raised; beneath rather dull, finely and densely punctured and pubescent, reddish-ochraceous 
or ferruginous, sometimes stained with piceous; legs more or less ochraceous or ferruginous, very stout in 
fully-developed males ; fifth ventral segment arcuate-emarginate in the middle in both sexes. 
Length 83-15 millim. (¢ 9.) 
Hab. Mexico, Jacale, Orizaba (Sal/é). 
Numerous examples. This fine species is labelled D. brachynoides, Chevr., in the 
Sallé collection. The head in fully-developed males is enormously enlarged; males 
of minor development and females approach D. mexicanus &c. in this respect. The 
species is exceedingly variable in size and colour, and also in the degree of development 
of the head in the male. Examples of it from Mexico are also contained in the National 
and other collections. D. brachinoides, as its name suggests, has much the facies of a 
Brachinus. 
A fully-developed male is figured. 
2. Ditylus longicollis. (Tab. V. fig. 22, 4.) 
Moderately elongate, rather convex, finely pubescent, above and beneath and the legs and antennz unicolorous 
brownish-ochraceous, the head and prothorax slightly shining, the elytra opaque. Head closely and 
minutely punctured, dilated behind the eyes, as wide as the prothorax—in well-developed males broader 
than the prothorax and much larger,—the eyes black, quite small, and not prominent; prothorax longer 
than broad, convex, the sides rounded in front and moderately constricted behind, the hind angles acute, 
the disc deeply impressed in the middle before the base, and with one or two vague impressions on each side 
anteriorly, the surface rather more finely and sparsely punctured than that of the head, a narrow longitudinal 
space down the middle of the disc impunctate; elytra comparatively short, rather convex, widest about 
the middle, very shallowly, minutely, and closely punctured, and with one or two very vague cost on the 
