Myrmicocrypta urichi, Neal A. Weber, University of North Dakota, 1936

Neal A. Weber, University of North Dakota, 1936, The biology of the fungus-growing ants. Part. I. New forms. 1, Revista de Entomologia 7, pp. 378-409 : 379-382

Myrmicocrypta urichi , sp. nov. (Figs. 2-3)

Worker: Length 1.9-2.1 mm. - Postpetiole from above about 1.8 times as wide as long, with convex sides diverging posteriorly. Anterior and posterior margins of first gastric segment straight, sides convex, slightly longer than wide. - Head and thorax opaque, finely shagreened; mandibles, first gastric segment, and appendages sub-lucid, finely punctate. - Pilosity of squamate to narrow-squamate hairs, moderately abundant except on thorax where confined largely to projections. - Thorax and appendages dark ferruginous, head and gaster dark brown.

Female (dealate): Length 3 mm. - Similar to the worker with the usual sexual differences. Scutum and scutellum in profile forming a slight convexity except for impression at their junction. Epinotal spines short but well-developed. Postpetiole from above in form of longitudinal 1/2 of an ellipse, 2 1/2 times as wide as long. First gastric segment coarsely striate at base, surface punctate. Color darker than in the worker.

Male: Length 3.4 mm. - Head, excluding mandibles, a trifle longer than wide back of eyes, occipital corners in form of obtuse angles, posterior pair of ocelli extending farther back than occipital angles, median ocellus on same level as angles. Behind each posterior ocellus is a small tubercle and behind these the head is transversely and deeply excised to the short neck. Anterior clypeal margin convex. Eyes hemispherical, not quite 1/2 length of head, excluding mandibles. Frontal lobes in form of high sub-vertical carinae not covering antennal insertions. Antennal scapes sub-cylindrical, extending as far as posterior border of median ocellus, as long as first two joints of funiculus taken together. Mandibles wellformed, triangular, with 6 distinct teeth on cutting edge and larger apical tooth.

Pronotum with 2 pairs of tubercles on each side, the more dorsal and posterior the larger. Scutum with a pair of longitudinal median carinae and carinae on margins, all with irregular small tubercles, each terminating posteriorly in a large tubercle. Scutellum irregularly bidentate behind. First gastric segment medially impressed, slightly wider than long.

Head and thorax opaque, shagreened, mandibles and first gastric segment semilucid, finely reticulate. - Pilosity of scanty, short, and recurved white hairs. - Black, appendages and mandibles ferruginous.

Described from one colony containing all castes taken by myself March 9, 1935, under coconuts bordering Mayaro Bay, Trinidad, B. W. I. The colony was collected and kept under observation until I left for British Guiana the following August. Additional information on this colony will be given in a subsequent paper.

Two colonies taken by myself June 25, 1935, in the Nariva Swamp, Trinidad, B. W. I., belong to this species. The workers are somewhat paler and show a certain variability in size of thoracic tubercles.

This species resembles M. buenzlii Borgmeier , also found in Trinidad. The worker, however, differs in arrangement of thoracic tubercles, in having shorter epinotal spines, in darker color and in other ways. The female differs chiefly in shorter pronotal and epinotal spines, reduced rugulosity of thorax, and in having smaller squamate hairs.

The male differs in having more deeply excised occipital region, longer antennal scapes, and higher pronotal tubercles.

1 take pleasure in dedicating this species to my friend Mr. F. W. Urich, the well-known naturalist of Trinidad, with whom 1 made many interesting trips about the island and whose hospitality I frequently enjoyed. His contributions to myrmecology date back nearly half a century.