Ochrotrichia attenuata Flint 1972

Ochrotrichia (O.) attenuata

Although a member of the lometa group, O. attenuata, new species, is easily recognized by the slender, pointed apex of the claspers. The structure of the tenth tergum, although quite similar to that of O. dactylophora Flint, is distinctive also in the shapes, lengths, and numbers of spines.

ADULT.—Length of forewing, 2.8 mm. Color fuscous; head with some whitish hairs, forewing with a transverse white band at midlength, several small white spots apicad, and with apex white. Male genitalia: Ninth tergum depressed and greatly expanded anteriad. Tenth tergum with two black-tipped spines basally, longest one with tip sharply upturned; right side with two short spurs and one long one ventrally whose tip almost reaches the apex; apical process inflated basally, tip decurved, subapically with a lightly sclerotized circular plate on right. Clasper elongate, tip produced into an attenuate, darkened point; with an elongate cluster of black peglike setae mesally at midlength. Aedeagus very long, threadlike.

MATERIAL.—Holotype, male. GUATEMALA: HUEHUETENANGO: 20 miles (32 km) northwest of Huehuetenango, 9–10 August 1967, O. S. Flint, Jr. USNM Type 72045. Paratypes: Same data, 2♂.

Species of the subgenus Metrichia have been found from the southwestern part of the United States, throughout Central America and the West Indies, and again from Peru, northwest Argentina, and central Chile. The greatest diversity so far found has been in Central America and the West Indies.

I recognize five groups for the species treated in this paper. The nigritta group is characterized by the presence of internal sacs arising between the fifth and sixth segments. The aedeagus bears two large hooks at nearly the midlength of the apical section. In addition to O. (M.) nigritta (Banks), the group contains O. (M.) arizonensis, new species, and O. (M.) biungulata, new species.

The second group is much like the former in the structure of the aedeagus, but the smaller internal pouches apparently arise between the fourth and fifth segments, there are dorsolateral hair brushes on the fifth and sixth segments, and the seventh tergum is modified. This group, the penicillata group, contains O. (M.) penicillata, new species, and O. (M.) trigonella, new species.

The campana group contains in addition to O. (M.) continentalis, new species, and O. (M.) quadrat a, new species, the species O. (M.) campana Flint and O. (M.) similis Flint from Dominica. The pouches are borne between the sixth and seventh terga in these species, the two aedeagal hooks are subapical, and usually the tenth tergum is elongate.

The exclamationis group bears pouches between the fourth and fifth terga, and also dorsolateral hair brushes on some segments. The aedeagus bears but a single elongate spine. In addition to the Dominican O. (M.) exclamationis Flint, the group contains O. (M.) lemniscata, new species.

The species O. (M.) aberrans, new species, is placed in its own group. There are no modifications of the abdomen, and the aedeagus ends in a bulbous lobe bearing two spines and a freely extending tubule.

The larvae inhabit compressed, purselike cases of silk and organic matter. The species of the subgenus seem to be closely associated with springs, seeps, waterfalls, and similar habitats, rather than larger, slowly flowing streams as is typical of the nominate subgenus. The adults are rarely taken at light, and when they are I expect it is the result of their having been disturbed. They are more frequently taken by sweeping vegetation at or near the water’s edge.