Smicridea (Rhyacophylax) arizonensis Flint 1974

Smicridea (R.) arizonensis

This species is a member of the signala group, closely related to S. salta, new species. The adults are larger and paler than those of S. salta. The male genitalia of S. arizonensis lack the sharp ventrolateral spine on the tenth tergite, and have a broader apicoventral process at the tip of the aedeagus than S. salta.

The internal plate of the female has broader lateral arms and anterior bridge than does the plate of S. salta, and the dorsal bridge of the ninth segment is proportionately longer in S. arizonensis.

ADULT.—Length of forewing 4.5–6 mm. Color brown; forewing nearly uniformly brown with a transverse white band at anastomosis (Figure 32). Fifth sternum with anterolateral process slightly shorter than sternum in male and less than half length of sternum in female. Male genitalia: Ninth segment with anterolateral process short, slightly upturned. Tenth tergite in lateral aspect with apex broadly upturned, ventral margin with a small lobe at midlength; in dorsal aspect with tip slightly produced. Clasper with basal segment long, slightly sinuate; apical segment bluntly pointed in dorsal aspect. Aedeagus tubular, with basal and apical sections meeting at about 120°; apex with ventral process straight, about two-thirds width of stem, dorsally with darkened apicolateral spots, internally with a long, paired, eversible structure. Female genitalia: Ninth tergum with anterolateral margin sinuate, not strongly produced. Internal plate in posterodorsal aspect U-shaped, with anterior bridge produced mesally; in lateral aspect with posterior arms rather short, and angled to axis of bridge. Vagina with anterior bar bearing very short, posteriorly directed processes laterally, with a pair of very small, lightly sclerotized plates posteriorly.

IMMATURE STAGES.—Unknown.

MATERIAL.—Holotype, male: U.S.A., ARIZONA, Clear Creek Campground SE of Camp Verde, 17 June 1968, Flint and Menke. USNM Type 72706. Paratypes: Same data, 54 25 .

BIOLOGY.—The adults were attracted to an ultraviolet light in company with adults of S. signala and S. dispar. The adjacent stream was 3–5 meters wide and flowing over shallow, gravel riffles.