OSMYLIDAE Leach, 1815

Winterton, Shaun L., Martins, Caleb Califre, Makarkin, Vladimir, Ardila-Camacho, Adrian & Wang, Yongjie, 2019, Lance lacewings of the world (Neuroptera: Archeosmylidae, Osmylidae, Saucrosmylidae): review of living and fossil genera, Zootaxa 4581 (1), pp. 1-99 : 13

OSMYLIDAE Leach, 1815 (‘lance lacewings’)

Type genus. Osmylus Latreille, 1802: 289 .

Diagnosis. Adult head with dorsal tentorial arms weakly developed; ocelli usually present, medial ocellus sometimes reduced (e.g., Paryphosmylus ) or all ocelli completely absent (e.g., Gumillinae ); palpimaculae absent; antennae filiform; wings with basal subcostal veinlet simple in costal area, sometimes forked but never recurrent; single basal crossvein (sc-r) between Sc and R, rarely more than one (e.g., Porismus , Archaeosmylidia ); Sc and RA fused apically and joining costal margin before wing apex in both wings; single branch of RP, subsequently pectinately branched (5 or more branches); FW radial branches frequently curved posteriorly in apical half of wing, sometimes sinuous; FW medial vein fork variably placed along wing, HW medial vein fork near wing base; FW CuP pectinately (rarely dichotomously) branched; cubital field relatively large in both wings; nygmata typically present; trichosors present in both wings (rarely reduced to apical margin); end twigging along wing margin present, sometimes extensive and multi-layered; jugal lobe present; female gonocoxite 9 (gx 9) (i.e., gonopophysis lateralis) elongate and with terminal stylus; female with a pair of sclerotised spermathecae; male genitalia with well-developed arched gonarcus with paired entoprocesses fused laterally; mediuncus curved; parameres present or absent, sometimes fused into single arched sclerite; larva ( Fig. 1 ) with straight, highly elongate jaws; gular-like sclerite absent; seven Malphigian tubules, of which five are incorporated into the cryptonephridium; eversible claws present on paired prolegs on last abdominal segment.

Comments. The monophyly of Osmylidae relative to other lacewings is unquestioned, based on a series of both adult and larval characters. The distinction of Osmylidae from Archeosmylidae and Saucrosmylidae is more problematic, and some authors consider the latter to be a subfamily of Osmylidae . Saucrosmylidae can be separated from Osmylidae based on the expanded area between veins RA and RP, with multiple rows of crossveins present. Archeosmylidae is differentiated from Osmylidae by the absence of pectinate branching in the posterior part of the wing and RP branches not sinuous distally. The larval characters listed here as synapomorphic for the family reflect our lack of knowledge of larval stages of closely related fossil families Saucrosmylidae and Archeosmylidae and the subfamily Mesosmylininae . Once larval stages are discovered for more Osmylidae and any of the fossil families, then the larval definition for Osmylidae may need modification. The family is divided into the nine subfamilies: Osmylinae , Kempyninae , Stenosmylinae , Gumillinae , Spilosmylinae , Eidoporisminae, Porisminae, Protosmylinae and Mesosmylininae . Beutel et al. (2010) provided a detailed study of the adult head morphology, MacLeod (1964) examined the head sclerites of the larva and Matsuno & Yoshitomi (2016) proposed terminology for the larval sclerites.

Figures

FIGURE 1. Larval stages of Osmylidae: A. Kempynus sp. (photo: Kristi Ellington); B. Isostenosmylus sp. (photo: Enio Branco); C. unidentified stenosmyline (photo: Kristi Ellington).