Cribrus concinnus

Cribrus concinnus (Sanders & DeLong) Figs 26–40, 41–43, 44–47 Deltocephalus concinnus Sanders & DeLong 1917: 86. Laevicephalus concinnus (Sanders & DeLong): Comb. Beamer and Tuthill 1934. Cribrus concinnus (Sanders & DeLong): Comb. Ross and Hamilton 1972. = Deltocephalus plagus Ball & DeLong, 1926: 241. New synonym. = Laevicephalus shingwauki Beamer & Tuthill, 1934: 19. New synonym. Description. Males 2.5–2.8 mm. Females 3.3–3.6 mm. Colour mostly light yellow, with two light brown longitudinal stripes on crown and four longitudinal stripes on pronotum. Legs with dark spots at bases of macrosetae. Abdominal tergites with four brown to black longitudinal stripes usually apparent. Abdominal sternites may have lateral brown markings. Fore wing pale brown with indistinct darker brown infuscation around border of cells. Wing length variable in females, from fully macropterous to brachypterous with fore wing reaching apex of tergite VI and hind wing reaching apex of tergite II. Males brachypterous with fore wing reaching base to midpoint of pygofer and hind wing reaching apex of tergite II to III. Subgenital plates bearing a single row of approximately seven macrosetae laterally. Style with medial lobe of apophysis finger-shaped. Aedeagus with long apical processes curving toward base, sculptured with complex ridges. Female sternite VII rectangular, posterior corners rounded, posterior margin straight to moderately convex, may have slight projections medially and laterally (Fig. 40). Gonoplac pale. Base of first valvula in ventral view elongate (Fig. 37). Material examined. Lectotype of Deltocephalus concinnus Sanders & DeLong (here designated). USA • ♀; Wisconsin, Ladysmith; 9 Aug. 1916; D. M. DeLong leg.; OSUC, OSUC 0171752. Holotype of Deltocephalus plagus Ball & DeLong. USA • ♀ (specimen missing from point, not examined); Wisconsin, Madison; 21 Sep. 1917; E. D. Ball leg.; USNM. Holotype of Laevicephalus shingwauki Beamer & Tuthill. USA • ♂ (apparently lost, not examined); Minnesota, Aitkin; 25 Aug. 1933; P. B. Lawson leg.; SEMC. Other material. USA – Illinois • 1 ♂, 3 ♀; 3 mi W Kankakee; 25 Aug. 1980; K. G. A. Hamilton leg.; CNC • 24 ♀; Fox Lake; 26 Jun. 1935; DeLong & Ross leg.; INHS • 2 ♂, 1 ♀; Fox Lake; 6 Aug. 1935; DeLong & Ross leg.; INHS • 3 ♀; Fox Lake; 26 Jun. 1936; Frison & DeLong leg.; INHS • 8 ♂, 7 ♀, 2 nymphs, approximately 20 unmounted specimens in a capsule; Iroquois Co., 7 mi NE Beaverville; 25 Sep. 1962; Ross & Ross leg.; from Calamagrostis canadensis; GL 177; CNC • 1 ♀; Zion; 16 Jun. 1954; Sanderson & Moore leg.; CNC. – Wisconsin • 1 ♂; Juneau Co., 6 mi NE Mather; 17 Jul. 1963; Smith & Stannard leg.; GL 654; CNC • 8 ♀; Wood Co.; 16 Jul. 1963; Stannard & Smith leg.; GL 666; CNC. Remarks. All males examined are brachypterous and clearly belong to a single species with distinctive genitalia. Females differing in wing length were previously treated as distinct species (e. g. DeLong 1948), but other structural features and colour pattern are consistent among specimens with different length wings. The examined series from Fox Lake, Illinois, collected on 30 June 1935, includes 23 brachypterous females with fore wing reaching the apex of tergites VI to VII and hind wing reaching the apex of tergites II to IV (all identified by D. DeLong as “ Laevicephalus shingwauki ”) (Figs 41, 42) and one macropterous female with fore and hind wings both exceeding the tip of the abdomen (identified by D. DeLong as “ Laevicephalus concinnus ”) (Fig. 43). The specimens are otherwise inseparable, and the best explanation for the wing length variation among females is the presence of a rare macropterous morph within a single species. Synonymies in the genus are complicated by the apparent loss of the type material of C. plagus and C. shingwauki, but the available evidence suggests both be treated as junior synonyms of C. concinnus. With the synonymies proposed here, Cribrus becomes a monotypic genus including only C. concinnus. Sanders and DeLong (1917) described D. concinnus from two female syntypes from the same locality. One of these was apparently later designated as the holotype of D. concinnus var. incisurus as discussed above. There is no published lectotype designation for D. concinnus, and so I here designate the other syntype (Figs 44–47) as lectotype to stabilize the application of the name. This appears to be the specimen illustrated under this name by Sanders and DeLong (1917) and DeLong (1926). The specimen was labelled as “ holotype ” in DeLong’s collection in OSUC. However, this label was probably added later by another worker (L. Musetti pers. comm. 2022) and is incorrect, as no holotype was originally designated. The lectotype is a macropterous specimen, but it is otherwise indistinguishable from other female specimens of the species. The holotype of D. plagus is missing from the point, with only a leg remaining (S. McKamey pers. comm. 2022). The original description and illustrations are both good matches to brachypterous females of this species. Oman (1949) suggested D. plagus was probably a synonym of C. shingwauki, although he did not formally synonymize them. The holotype and a male paratype of Laevicephalus shingwauki are stated in the original description to be deposited in the SEMC, but they can not be located there now (R. Osborn pers. comm. 2024). Beamer and Tuthill (1934) separated their species from C. concinnus based on the smaller size, shorter wings, and abdominal colouration, although they speculated it might actually be the male of the former. Ross and Hamilton (1972) later also suggested that C. concinnus was “ close to if not the same species as C. shingwauki. ” Although the internal genitalia of the type series were not described, the description of the external characters and illustration of the external genitalia are a clear match to the present concept. The differences in size and abdominal colouration mentioned by Beamer and Tuthill (1934) both represent sexual dimorphism within the species. Females of this species can be separated from Boreolimnus and other Nearctic Paralimnini with longitudinal stripes on the head and pronotum based on the longitudinal dorsal stripes on the abdomen, outer anteapical cell well developed and closed by crossvein s, sternite VII entirely pale with rounded posterior corners and without medial emargination, and pale gonoplacs. Distribution. Found in the midwestern United States (Minnesota to Indiana), around the eastern margin of the tallgrass prairie region (Fig. 25). Host plants. Associated with Calamagrostis, usually in mesic to wet prairie or wetlands (DeLong 1948; Panzer et al. 2003; J. Bess pers. comm.; examined specimens).