Nymphomyia dolichopeza Courtney, 1994
Adults: Small, delicate, elongate flies; length typically about 2 mm. Wings deciduous, narrow, fringed with long macrotrichia; venation reduced. Legs similar, long and thin; femur and tibia superficially bi-segmented. Terminalia directed ventrad. Larva: Body typically 1 to 2 mm in length, compressed laterally, lightly sclerotized except head capsule, which is well developed and visible (eucephalic). Antenna elongate, one-segmented. Thoracic segments distinct; appendages absent. Abdomen nine-segmented; segments I-VII and IX with paired, crochet-tipped ventral prolegs. Anal papillae four in number. No specialized breathing apparatus (apneustic). Body surface mostly glabrous, with few setiform sensilla.
Larva: median tooth of postmentum projecting anteriorly to level of adjacent lateral teeth and with one pair of lateral serrations; lateral teeth without lateral serrations, notch between lateral teeth I and II as deep as notches separating other teeth. Pupa: rostral hooks divergent, abdominal stemites III-VII with hooks, tergites II-VII with spine rows. Adult: ommatidia of compound eyes (two pair) contiguous ventrally; male with empodium of foretarsus longer than tarsal claw and gonostylus bifurcate, anterior branch broader than posterior branch; female abdominal segment VIII without lateral flaps but anteriorly with circular zone of glabrous cuticle bearing curved lobes and depressions.
Head: Adult ♂: Rostrum apically truncate Cranium glabrous anterodorsally, from apex of rostrum to near posterior margins of eyes; microtrichia absent posteroventrally. Ommatidia of compound eyes contiguous ventrally, contact between two pairs of facets; microtrichia between dorsal facets only. Terminal sensilla of antenna apical.
Legs: Empodium of foretarsus elongate, extending beyond apex of tarsal claws; claws without prominent basal tooth
Male abdomen: Stemites V and VI and tergite VIII simple, without elongate processes. Membrane between tergites VIII and DC with clusters of setiform sensilla. Gonocoxites reduced, fused broadly and indistinguishably to cerci, surface generally invested with fine microtrichia. Gonostylus bifurcate, anterior branch markedly broader than posterior branch, invested with microtrichia; posterior branch glabrous, with 2 to 3 apical sensilla. Aedeagus short, thick, broad basally, constricted subapically, thickened distally; when not exserted, extending anteriorly only to abdominal segment VIII; aedeagal rod extending from base of aedeagus to slightly beyond subapical constriction; aedeagal sheath short, broad basally, more or less continuous with base of aedeagus, sparsely set with lateral microtrichia.
Female abdomen: Similar to male. Terminalia: Abdominal segment VIII without lateral flaps but anteriorly with circular zone of complex, glabrous cuticle bearing curved lobes and depressions (receptacle for male gonostylus). Abdominal segment DC with slightly developed lateral flaps; tergite densely set with microtrichia, stemite mostly glabrous except for pubescent medial depression. Cerci (?) broad, directed posteriorly.
Larva: Postmentum not trilobed anteriorly; median tooth projecting anteriorly to level of adjacent lateral teeth and with one pair of lateral serrations; lateral teeth without lateral serrations; notch between lateral teeth I and II as deep as notches separating other lateral teeth.
Puparium: Rostral hooks elongate, divergent; antennal sheath elbowed. Microsculpture: abdominal stemites III-VII with one pair of posteriorly directed hooks; tergites 11-VII with posterior spine rows. Anal hooks elongate, with small dorsal serrations. Segment DC sexually dimorphic: male with circular, posteroventral lobes; female without lobes.
Length: Larvae: 1-2 mm; Adult: 2 mm
Larvae occur on mossy rocks in small, cool, pristine streams; there they graze or collect/gather microorganisms and plant matter. Pupae can be found in the same habitats. When adults emerge, they may form swarms (based on observations of other species), where they couple. Both male and female crawl underwater (usually losing their wings in the process) where the female lays a rosette of eggs around the still-coupled bodies. After mating and laying eggs, the pair dies. Nympohomyia dolichopeza appears to be multivoltine.
Southern Blue Ridge Mountains of eastern U.S.A., being most abundant in tributaries of the upper Tennessee River drainage. In addition to North Carolina and Georgia, the species evidently occurs in northwestern South Carolina, primarily in the Lake Jocassee drainage.