Allotrichoma jamaicense Mathis 1991

Allotrichoma (Pseudohecamede) jamaicense

DESCRIPTION.—Small to moderately small shore flies, length 1.60 to 2.10 mm.

Head: Proclinate fronto-orbital seta present, subequal in length to reclinate seta; pseudopostocellar setae present, about ¾ length of ocellar setae. Arista with basal thickened portion short, about ⅓ total aristal length; arista bearing 4–5 dorsal rays, basal 3 subequal in length. Face of male and female unicolorous, brown, concolorous with frons; facial carina ended ventrally as a subshiny to shiny tubercle; lower facial margin shallowly emarginate.

Thorax: Presutural seta either absent or inconspicuous, similar to surrounding setulae; acrostichal setulae in 4 rows although lateral rows with sparse to no setulae anteriorly; mesonotum and pleural areas brown, becoming more thinly microtomentose ventrally, subshiny, lacking horizontal stripes. Wing hyaline; veins pale colored, costal vein yellowish, those behind whitish; costal vein ratio 0.47; M vein ratio 0.36. Legs, except for tarsi, grayish to grayish brown; tarsi with basal 3 tarsomeres yellowish, apical 2 grayish brown. Abdomen: Terga brown, microtomentum sparse laterally, subshiny to shiny. Male terminalia (Figure 27) as follows: Epandrium in lateral view narrowly developed, a narrow band, posteroventral angle distinctly produced; cercus well develdeveloped, width about twice that of epandrium; surstylus moderately developed comparatively, narrow, length less than width of cercus, apex slightly pointed; aedeagal apodeme with basal portion small, irregularly shaped, with a short posterior projection, which attaches to the hypandrium, and a longer dorsal projection, which attaches to the base of the aedeagus; aedeagus simple, more or less parallel sided, apex moderately rounded; gonite as an irregular rectangle, posteroventral angle produced, but only slightly more than 2 other projections along posterior margin, anterodorsal surface shallowly concave; hypandrium in lateral view slightly angulate, ventral arm longer but no more robust than dorsal arm.

TYPE MATERIAL.—The holotype male is labeled “JAMAICA Wag Water Rpver]. 25 Feb. 1969 W.W. Wirth stream.” The allotype female and six paratypes (4, 2; USNM) are labeled “JAMAICA Runaway Bay Feb. 1969 W.W. Wirth stream bed.” Other paratypes are as follows: JAMAICA. Annotto Bay (marsh), 25 Feb 1969, W.W. Wirth (1, 1; USNM). The holotype specimen is double mounted (minute nadel in a polyporous block), is in good condition, and is deposited in the Smithsonian Institution (USNM).

DISTRIBUTION (Figure 26).—West Indies: Jamaica.

ETYMOLOGY.—The species epithet, jamaicense, is a Latinized geographical name meaning from the island of Jamaica.