Key to the Adults of Extant Nearctic Megaleuctra

Males

1 Tip of subanal probe acute or threadlike (Figs. 21- 22, 25, 29, 75, 77, 81); known distribution Appalachian Mountains region of eastern North America.………………………………….…….… 2

1’ Tip of subanal probe enlarged and bearing a subapical notch (Figs. 3, 10, 16, 36, 64, 68); known distribution northern Rocky Mountains, Sierra Nevada and Cascades of western North America ……………………………..……..….... 3

2 Tergum 9 bearing a small, darkly sclerotized, median, toothed process between low lateral lobes (Figs. 21, 28); subanal probe expanded above base and about mid length, tip thread-like (Figs. 21, 22, 25, 29); known from Maryland, Pennsylvania, West Virginia and Shenandoah National Park, Virginia ……………..…… M. flinti

2’ Tergum 9 without median process or low lateral lobes (Figs. 74, 78); lateral aspect of subanal probe relatively uniform in diameter throughout, tip truncate (Fig. 75, 81); known from North and South Carolina, Tennessee and the Mount Rogers area of southwestern Virginia ..….. M. williamsae

3 Tergum 9 bearing large pair of rounded dorsal processes near posterior margin, anterior margin of process rounded, posterior margin angled abruptly downward, lateral profile forming a broad arc (Figs. 55, 67), cerci short … M. stigmata

3’ Tergum 9 bearing smaller pair of processes near posterior margin, processes thinner and pointed at apex, cerci long (Figs.3, 5, 36, 42) ..................… 4

4 Processes on tergum 9 relatively symmetrical, broad basally, narrowed apically and bluntly pointed or conical at tip (Figs.6, 13), dorsal lobe of subanal probe long, thin and pointed at tip (Fig. 14), epiproct large, bearing large downward directed hooks medially when partially expanded (Fig. 9), hooks extending to apex of subanal probe when fully expanded (Fig. 8), ventral portion forming an elongate triangle when viewed dorsally (Fig. 6) ……………………… M. complicata

4’ Processes on tergum 9 thin, delicate, long and abruptly pointed (Figs. 36, 38), distal portion of subanal probe broad, and diamond shaped, with a small thin tip (Figs. 46-47), epiproct extending to near tip of unexpanded subanal probe (Fig. 42), but reaching far short of expanded probe (Fig. 48), thin tips not very conspicuous when expanded (Figs. 46, 50), hooks less obvious when extended to apex of subanal probe, ventral portion forming a stout triangle when viewed dorsally (Fig. 35) ……..……………………….………….… M. kincaidi

Females

1 Known distribution Appalachian Mountains region of eastern North America ………….…… 2

1’ Known distribution northern Rocky Mountains, Sierra Nevada and Cascade Mountains of western North America ……………….….……….……… 3

2 Subgenital plate (ovipositor) almost subequal in width from beyond base to apex (Fig. 83), known distribution North and South Carolina, Tennessee and Mount Rogers area of southwestern Virginia ………..…………………..……….…. M. williamsae

2’ Subgenital plate (ovipositor) narrowed conspicuously from base to apex; known from Maryland, Pennsylvania, West Virginia and Shenandoah National Park, Virginia.…… M. flinti

3 Stigma beyond cord large, darkly pigmented and filling most of costal space; usually more than 3 branches of radial sector vein (Fig. 1) .. M. stigmata

3’ Stigma beyond cord small, less darkly pigmented and filling less than half of coastal space; usually 2 or 3 branches of radial sector vein (Fig. 85).……….………..……….... M. complicata / M. kincaidi