Cylindromyrmex darlingtoni

The northermost occurring species in the genus, it is only known from the types. These were collected in decaying wood.

Identification
This species is peculiar in the structure of the mandibles in the worker and female, and in the retention of distinct promesonotal and mesoepinotal sutures by the former.

Distribution based on Regional Taxon Lists
Neotropical Region: Cuba, Greater Antilles.

Nomenclature

 *  darlingtoni. Cylindromyrmex (Hypocylindromyrmex) darlingtoni Wheeler, W.M. 1937b: 441 (w.q.) CUBA. See also: De Andrade, 1998a: 622.

Worker
Length 5.6-6 mm.

Head sub oblong, one third longer than broad without the mandibles, as broad in front as behind, with straight, parallel sides and angularly excised posterior borders. Eyes small, flat, nearly as long as the greatest diameter of the antennal scapes, one third as long as their distance from the posterior corners of the head and situated at its posterior two-fifths. Ocelli minute but distinct. Mandibles large and convex, with evenly rounded external borders, the apical borders broad, with about 10 subequal, low, blunt teeth. Antennal scrobes, clypeus and frontal lobes of the usual conformation. Frontal area distinct, elongate-lanceolate. Antennal scapes less than three times as long as broad; first funicular joint as broad as long, joints 2-7 more than twice as broad, 8th as broad as long, the large terminal joint as long as the 9th and 10th together. Thorax short, somewhat less than twice as long as broad, parallel-sided, semi circularly rounded behind, with rounded humeri and short neck; promesonotal and mesoepinotal sutures distinct, interrupting the sculpture but not impressed. In profile the thoracic dorsum is nearly flat, the sides of the pronotum marginate, of the meso- and epinotum submarginate, the declivity of the latter abrupt, forming nearly a right angle with the base. Petiole distinctly longer than broad, with a blunt tooth at each of its anterior corners, the node distinctly widened behind and in this region with rounded, convex sides; in profile the anterior surface is flat and perpendicular, the dorsal surface evenly convex. The anteroventral process of the petiole is large, subrectangular in profile, and laterally compressed. Postpetiole about one and two-thirds times as broad as the petiole and a third broader than long. Gaster long but not much broader than the postpetiole. Pygidium truncated posteriorly and beset with numerous spinules. Legs short, the femora and tibiae broad and flattened, the hind tarsi decidedly longer than the hind tibiae, which are furnished with a long and a short pectinated spur.

Shining; mandibles finely striate and coarsely punctate apically, smooth at the base; head including the scrobes, thorax, petiole and postpetiole rather finely striate, the striae occasionally interrupted by sparse, elongate, piligerous punctures; pleurae and first gastric segment more finely striated, but the latter only on the anterior half where it is also coarsely and sparsely punctate. Remaining gastric segments, scapes and legs smooth, with numerous fine, superficial punctures.

Erect hairs yellowish, sparse, delicate, moderately long, of uneven length. The anterior border of the gula bears a conspicuous fringe or tuft of bristles, and there are some long, sparse hairs along the ventral surface of the lateral borders of the mandibles and a few long deflected hairs on the anterior, truncated surface of the clypeus. Pilosity sparse on the legs, most abundant on the tarsi. Gastric segments distinctly pubescent.

Black; tips of scapes, funiculi, legs and pygidium brownish red. femora dark brown, terminal funicular joint and tarsi, except the basitarsi, paler and more yellow.

Queen
Length 7.5-8 mm.

Closely resembling the worker. The head is not longer in proportion to its width but the eyes are much larger though only feebly convex, as long as their distance from the posterior corners of the head. Ocelli larger than in the worker. Scapes broader, with their anterior border more strongly excised at the base. Thorax long; pronotum, without the neck, subtrapezoidal, nearly twice as broad as long, with straight, submarginate, posteriorly diverging sides. Promesonotal suture semicircular, distinct and impressed. Mesonotum and scutellum small and flat. Gaster longer than in the worker owing to a lengthening of the individual segments. Wings short (5 mm.)

Sculpture very much like that of the worker but the striae on the posterior portions of the mesonotum and scutellum and dorsal portion of the mesopleurae feeble or absent, so that these regions are smoother and more shining. Gaster more densely punctulate than in the worker. Pilosity and color as in that caste. Wings grayish hyaline, veins dark brown, pterostigma black.