Stonefly Species Megaleuctra stigmata (Little Black Needleflies)

Source: The Genus Megaleuctra Neave (Plecoptera: Leuctridae) In North America

Male. Macropterous. Length of forewing 14 - 15 mm; body length 12 - 13 mm. General color brown. Wings hyaline, with dark stigma in costal space occupying more than half the costal space beyond the cord. Radial sector of forewing with 2 - 5 branches. Tergum 9 with a pair of large narrowly separated lobes, apically blunt, slanted posteriorly; darkly sclerotized forked structure at base, with long setae (Figs. 54, 55, 61); subgenital plate tongue-like, apex rounded, sometimes upturned (Figs. 55, 70); vesicle at base of sternum 9 long, and narrow. Tergum 10 with ventrobasal expansion darkly sclerotized, elongate, tip emarginate (Figs. 55, 61); epiproct broad at base dorsally, with large middorsal groove (Figs. 57, 65), forming rounded fork at apex, bearing small rounded processes laterally, ornamented with narrow leaf-like lobes, when expanded (Figs. 58, 62); epiproct stout and broad, rectangular dorsally, with large, paired, downward forked apical processes when in mid-length position (Figs, 65, 67), when expanded, broader at base, terminating in narrow apex, which surrounds apex of subanal probe (Figs. 54, 55, 57, 61). Subanal probe directed upward, fitting in middorsal groove of epiproct (Figs. 54, 57, 61, 62), tip expanded, with subapical notch in lateral view (Figs. 64, 68), upper lobe small, arched dorsally, with a pointed tube bearing apex, lower lobe large and broadly rounded (Figs. 60, 64, 66, 68). Cerci single segmented, elongate (Figs. 54, 55, 59, 70).

Female. Macropterous. Length of forewing 16 - 18 mm; body length 19 - 20 mm. Coloration similar to male. Radial sector of forewing with 2 - 5 branches, intercubital crossveins 15 - 20. Sternum 8 with subgenital plate extending past tip of abdomen 1.5 - 2.0 mm, narrowing gradually to tip, round in cross section (Fig. 56). Sternum 9 forming a long, narrow ovipositor (Figs. 71, 72).