Sericomyrmex urichi Forel maracas

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 : 394-396

Sericomyrmex urichi Forel maracas , subsp, nov.

(Fig. 7)

Worker: Length 2.8-3.5 mm.

Head, excluding mandibles, 0.9 as long as wide, broadly impressed on posterior margin. Antennal scapes failing to reach occipital angles by a distance about equal to their smallest diameter. Antennal scrobes feeble, indicated above frontal lobes more by absence of coarse hairs than by carinae. Terminal joint of funiculus distinctly longer than joints 7-9 taken together and nearly as long as joints 2-6 taken together. Joints 2-8 of funiculus broader than long, ninth joint about as long. - Thorax and pedicel in profile as illustrated (Fig. 7). First gastric segment laterally with faint ridges.

Body covered with numerous sub-appressed coarse hairs and with interspersed abundant fine yellowish hairs forming an appressed pubescence. - Pale, dull ferruginous.

Female: Length 4.9-5.3 mm. - Head, excluding mandibles, 0.9 as long as wide, broadly impressed on posterior margin. Antennal scapes proportionately a little shorter than in the worker. Proportions of funicular joints as in worker. Epinotum with low, obtuse epinotal tubercles. First gastric

segment with well-developed lateral ridges. Wings unevenly infuscated, veins brown, darker on margins. Pilosity as in worker. Color distinctly darker than in worker.

Male: Length 3.6 mm. - Head, with mandibles, pentagonal, posterior margin flat, sides, above eyes, flat; eyes convex, as large in diameter as sides between them iand occipital angles. Head, from occipital to clypeal borders 0.85 as long as distance between external borders of eyes. Antennal scapes nearly straight, 0.6 as long as funiculus. Antennal club 4-jointed, terminal joint slightly shorter than joints 8-10 taken together or joints 2-7 of funiculus taken together. Epinotum smoothly convex. Dorsal surfaces of pedicel convex, without projections other than hairs. Wings infuscated as in female.

Described from one colony taken by myself October 1, 1935, in the Maracas Valley of the Northern Range, Trinidad, B. W. I. The ants were nesting between the exposed roots at the base of a tree on the side of the valley. Nest opening a crater just remade after recent rains. This led obliquely by a tunnel 8 cm. into the bank to a spherical chamber 6 cm. in diameter containing the fungus garden pendant from roots.

This form differs from typical urichi chiefly in smaller size, in having larger posterior mesonotal tubercles, deeper mesoepinotal depression, more appressed pilosity, and in paler and duller color. 1 have taken the typical urichi numerous times in this same valley.