Gyrophaena (Phaenogyra) gracilis Seevers 1951

29. Gyrophaena (Phaenogyra) gracilis Seevers

Figs 1–3, 28, 184–191; Map 24

Gyrophaena (Phaenogyra) gracilis Seevers, 1951: 727; Moore and Legner 1975: 429.

Description. Body length 1.3–1.5 mm, dark brown with light brown pronotum. Punctation: vertex of head, pronotum and elytra evenly punctate (Fig. 1). Microsculpture: reticulate throughout. Antennae light yellow-brown as illustrated (Fig. 1). Pronotum 1.2 times as wide as long. MALE: tergite 8 with two large lateral teeth, and two small teeth, apical margin slightly emarginate medially (Fig. 182);

Map 24. Collection localities in New Brunswick, Canada of Gyrophaena gracilis

28. G. gracilis 29. E. corruscula 30. E. socia

Figures 28–30. Gyrophaena and Eumicrota species in dorsal view (apical part of abdomen removed in Fig. 29): 28 G. (P.) gracilis Seevers 29 E. corruscula (Erichson) and 30 E. socia (Erichson).

sternite 8 rounded apically (Fig. 183). Median lobe of aedeagus with elongate and apically divided tubus (Figs 184, 185), its base may be slightly swollen basally (Fig. 184), apical projection of internal sac short and irregularly shaped (Figs 184, 185). Paramere as illustrated (Fig. 186). FEMALE. Tergite 8 truncate apically (Fig. 190); sternite 8 broadly rounded apically and pointed medially (Fig. 191); spermatheca as illustrated (Fig. 189). Despite its distinctive external morphology, G. gracilis has genital structures very similar to those of G. meduxnekeagensis and G. subnitens (Figs 161–174).

Bionomics. Macrohabitat: Silver maple swamp, flood plain forest, red oak forest. Microhabitat: on Trametes hirsuta (Wolfen) Pilat growing on Populus tremuloides log (two sites), partially dried Pleurotus sp. on dead standing trembling aspen (one specimen) and one specimen from nest contents of barred owl (Strix varia Barton) nest box with small chicks. Collecting period: May, June, and August. Collecting method: sifting mushrooms and aspirating specimens.

Distribution (Map 24). CANADA: New Brunswick; UNITED STATES: Wisconsin.

Comments. Gyrophaena gracilis is externally the most distinctive species of the genus. Unlike other Gyrophaena species it has an extremely elongate postocular temple area of the head with sides subparallel for most of its length (Fig. 1), a small, evenly punctate pronotum (Fig. 1) and a swollen abdomen (Figs 1, 2). Adults of this species occurred within the pores of the host mushrooms. The elon- gate body of this species would appear to be an adaptation allowing this species to enter the pores of its host.