CALOPUS.—MICROTONUS. 113 
coarsely punctured; beneath finely and rather sparsely punctured ; legs slender; fifth ventral segment 
feebly emarginate in the middle in the male. 
Length 8 millim. (<¢.) 
Hab. Mexico, near the city (Hoge). 
One male example. Narrower, more depressed, more parallel, and much less coarsely 
punctured than either of the preceding species, the thorax less rounded at the sides 
anteriorly and broader in front, the legs more slender. 
e 
MICROTONUS. 
Microtonus, Leconte, Class. Col. N. Am. p. 259 (1862); Leconte & Horn, Class. Col. N. Am. 
pp. 404, 405 (1883). 
This genus is referred by its author to the Gidemeride. Jtcrotonus has hitherto 
only contained a single species from the United States; the six from Central America 
here included in the genus differ considerably amongst themselves, and one or two of 
them approach Symphora so closely that they might almost equally well be placed in 
it. The typical representatives of Microtonus and Symphora have, it is true, a different 
facies; but this is bridged over by the numerous additional species referred to these 
genera in this work. ‘The structure of the maxillary palpi, antenne, legs, &c. seems to 
be almost identical; and, apparently, the only difference of importance is the rather 
longer mesosternum and more widely separated middle cox in Microtonus, the middle 
coxee being about equally exserted in both. The thorax in both genera is without 
distinct lateral suture, and it varies in shape in the different species—in typical 
Microtonus it is subquadrate, sinuate behind, and with the hind angles acute, and in 
Symphora short and subtrapezoidal; the transverse frontal suture of the head is also a 
variable character, it being very distinct in some species and almost or quite obsolete in 
others; the penultimate joint of the tarsi is feebly lobed beneath, and the basal joint 
of the hind pair is very long in both. Microtonus would probably be better placed in 
the Melandryide, after Symphora; but for the purposes of this work the position 
assigned to it by Leconte is adopted for the present. Some of the Central-American 
species referred to it (and to Symphora also) will no doubt have to be separated 
eventually ; but with our wholly insufficient material it is inadvisable to propose new 
genera for these intermediate forms. 
The Central-American species may be separated thus :— 
Body elongate or moderately elongate. 
Eyes comparatively large, oblique; upper surface opaque, the pubescence 
short and fine. | 
Frontal suture distinct ; elytra spotted ; pubescence variegate . . jfiguratus. 
Frontal suture indistinct ; elytra unicolorous; pubescence uniform. gracilis. 
BIOL. CENTR.-AMER., Coleopt., Vol. IV. Pt. 2, December 1889. QQ 
