Macronema esterum Flint 1983

Macronema esterum

This species, M. reinburgi Navás, and M. exophthalmum Flint are easily recognized by the very large, bulging eyes in the male (at least). It is most closely related to M. reinburgi, which also bears a mass of appressed spines at the tip of the aedeagus but differs slightly in the details of this area. Unfortunately the specimens were in envelopes for years and now are so badly rubbed that the color pattern is unrecognizable and cannot be compared to related species.

ADULTS.—Length of forewing, 11 mm. Color brown (but see above). Eyes very large, almost touching dorsally; facets ventrally smaller than those dorsally, 2 areas separated by a distinct difference in curvature. Fifth sternum of male abdomen laterally with a narrow, raised boss.

Male Genitalia: Ninth segment annular, slightly produced dorsomesally. Tenth tergum sclerotized ventrolaterally, apex truncate. Clasper long, slender, parallel-sided; in ventral aspect curved, but not semicircular. Aedeagus enlarged basally, apex sharply angled ventrad; tip laterally bearing many appressed spines, with a midventral tonguelike sclerite; internally with a complex of sclerites.

MATERIAL.—Holotype (male): ARGENTINA, PCIA. CORRIENTES, C. Pellegrini, Oct 1966, I. Apostol. (MACN).

Paratypes: Same data as holotype, 4.

This is the only genus of Hydropsychinae known to occur in South America. Species are found from the southwestern United States to the tip of South America and in Australia. The genus is divided into two subgenera, the typical one in the male sex bearing two pairs of reticulate sacs in the abdomen, and the subgenus Rhyacophylax lacking these sacs. It is the dominant genus in most parts of Latin America, both in terms of numbers of species and individuals. Currently about 60 species of Smicridea (Smicridea) and 40 of Rhyacophylax are described, but this is only a fraction of the species in the Neotropics. Every collection from a different area in South America produces more previously unknown forms.

Larvae of species in both subgenera are described (Flint, 1974a; Ulmer, 1909; Wiggins 1977). They construct a rather typical retreat with trap-nets in flowing water. Apparently they feed on suspended organic matter trapped by the nets.