(Figs. 192–199)

As described for Robustagramma biangulatum except as follows.

Body length 1.6–2.0 mm. Facial ridge of male with width between antennae similar to width of scape; facial ridge of female distinctly broader between antennae than width of scape. Eye height ca. 2.7 times genal height. Mid femur of male with a row of strong anteroventral setulae in addition of over 10 ventral proximal bristles.

Male terminalia: Sternite 5 with 3–4 pairs of stout bristles. In lateral view, posteroventral margin of surstylus rounded. Ejaculatory apodeme ca. 1/3 as long as aedeagal apodeme. In anteroventral view, distiphallus with distal dorsal sclerites conspicuously extended outwardly.

Female terminalia: Spermathecae distinctly short and thick; single spermatheca with distal portion similar in length to basal portion; paired spermathecae with ducts nearly twice length of spermatheca.

Holotype (♂, DEBU) and paratypes (3 ♀, DEBU): VENEZUELA: Bolívar. Evergreen Dry Forest, FIT, vi– 12.vii.1987, S. & J. Peck.

Other paratypes: GUYANA: Rupununi Dist., Kurupukari, Essequibo R., 200ft, primary rainforest, dung traps, 9.x.1990, B. Hubley (6 ♂, 3 ♀, DEBU); Kurupukari, E. side Essequibo R., primary rainforest edge/field, malaise trap, 7–11.x.1990, B. Hubley and L. D. Coote (1 ♀, DEBU). VENEZUELA: Bolívar. 8 km N Guri, 200m, 16.vii–11.viii.1986, B. Gill (1 ♂, DEBU).

Etymology: The specific epithet refers to the short, thick spermathecae of this species.

Comments: Robustagramma crassisaccus is identical to Robustagamma ovipennis (Duda) in many details, even in shapes of surstylus and cercus. Robustagramma crassisaccus, however, differs in the form of male sternite 5, having 3–4 pairs of short, stout bristles. Furthermore, the distal sclerite of the distiphallus of R. crassisaccus lacks medial spicules.