Stenolysmus extraneus (Walker, 1853)

Cousin, Guillaume & Béthoux, Olivier, 2016, The steps towards an inconspicuous vein fusion documented in Stenosmylinae forewings (Neuroptera: Osmylidae), Organisms Diversity & Evolution (New York, N. Y.) 16 (1), pp. 225-232 : 228

Stenolysmus extraneus

Both wing pairs subequal; fore- and hind wing about 22.2 and 20.1 mm long, respectively, oval, slightly pointed apex; RP with about 10–12 main branches, with 27 to 33 terminal branches; nearly all vein branches between MA and CuA (included) terminated by a fork near wing margin. Forewing (Fig. 2a, b, d–g): MA fused with R short before the arising of RP+MA or opposite to it; RP and MA diverging less than 2.0 mm distal to the fusion; MP1 and MP2 diverging at wing mid-length; MP and MP1 aligned; MP2 diverging obliquely, with an orientation distinctive from that of cross-veins; MP2 distinct from (Fig. 2a, f), or fused with CuA (Fig. 2b, d, e, g) for a long distance (− 0.24 mm / 1.4 mm / 2.7 mm; 0.9 mm); MP2 and CuA first branched distal to their divergence point (i.e. no pectinate fusion of CuA with MP2); MA forked very distally, MP1 with an average of 4.2 branches (ranging from 4 to 5; dichotomously branched), MP2 with an average of 7.8 branches (ranging from 6 to 10; overall posteriorly pectinate), CuA with an average of 4.4 branches (ranging from 4 to 5; dichotomously branched), CuP with an average of 18.3 branches (ranging from 13 to 22; posteriorly pectinate). Hind wing: no clear origin of MP2 as herein identified (see B Discussion^).