Diplocheila (Neorembus) latifrons darlingtoni Ball 1959

Diplocheila latifrons darlingtoni, 3 new subspecies
The diagnostic features of this subspecies are presented above in conjunction with the distinguishing features of D. latifrons latifrons. The two forms overlap broadly with respect to overall size, in length of the mandibles, elytral length, and in the ratio length of left mandible/ elytral length (see tables 11-15), although there are average differences between the two in these characters. However, when the above ratio is considered in conjunction with elytral length (a measure of overall size, but more easily and rapidly measured) the two subspecies are clearly separated from one another ( see graph 1 ) . I choose not to regard them as different species because of their general similarity in all other structural characters, excluding the slight differences in configuration of the lateral margins of the pronotum.
An individual specimen of latifrons may be determined to subspecies by plotting its mandibular-elytral ratio against elytral length in graph 1 and observing where the point determined falls with respect to the two groups of specimens included here.
Description. — Type, female, Central Plain of Luzon, P. [hilippine] I. [slands], Feb.-Sept, 1945, (Darlington), [Museum of Comparative Zoology Coll.].
Female. Length 13.8 mm., width 6.0 mm. General proportions as in the typical subspecies but seemingly more slender. Color and sculpture as in typical subspecies.
Head with frontal impressions punctiform and moderately deep, extending posteriorly to plane of anterior pair of supraorbital setigerous punctures, front between impressions with a small concavity, which extends also on to posterior margin of clypeus. Clypeus strongly transverse, 8.60 times wider than long, 2.30 times wider than labrum, slightly concave in vertical plane, anterior margin broadly emarginate, exposing basal margin of labrum. Labrum sexsetose broadly and deeply emarginate, base of emargination broadly rounded, not angulate, 1.81 times wider than long, width 6.15 times greater than minimum length, maxi-
3 This subspecies is named after its collector, Dr. P. J. Darlington, Jr., who loaned me this fine series of specimens and gave me permission to describe it. mum length 3.26 times greater than minimum length ; lobes narrowing strongly but evenly from base to apex, apex of each lobe narrowly rounded. Mandibles as described for typical subspecies but more elongate.
Pronotum as in fig. 33 with anterior margin moderately concave, sides moderately arcuate and reflexed more broadly so anteriorly than posteriorly causing sides to appear strongly constricted posteriorly, anterior angles rounded, posterior angles narrowly rounded ; dorsal surface as in typical subspecies ; apex of metepimeron broadly rounded.
Elytra with striae moderately deeply impressed, as in typical subspecies.
Female stylus as in typical subspecies.
Allotype. — Same data as for type.
Male. Differs from the female in no essential features. Length 13.0 mm., width 5.6 mm. Head 2.24 times wider than long, frontal impressions somewhat shallower and more elongate than in type. Clypeus 10.0 times wider than long, 2.18 times wider than labrum. Labrum 1.84 times wider than long, width 5.75 times greater than minimum length.
Pronotum with posterior angles slightly more rounded than in type.
Abdominal sternites laterally somewhat more rugose than in type.
Median lobe as in typical subspecies.
Variation.— Data on variation in the following mensural characters and ratios are presented in tables 11-15 — total length, length of elytra, length of left mandible, L left mand./L elytra, labrum : max. L/min. L. Usually the frontal impressions are as described for the allotype, but there is some variation in shape and depth, the average condition resembling that described for the allotype. The pronotum is as described for the type, with exceptions : two males with sides more broadly rounded medially, three females with sides more constricted posteriorly. Sculpture varies slightly.
The female retractile stylus does not exhibit any appreciable variation in shape. Setae on the outer margin vary in number from two to four (usually two), inner margin with a single seta. The median lobe of the male genitalia does not exhibit any noticeable variation.
In addition to the type and allotype, sixteen males and fourteen females, paratypes, have been dissected and examined, all with the same locality data as the type. Sixteen paratypes are retained in my collection. The type and the remaining paratypes have been returned to the Museum of Comparative Zoology.