Key to species of the genus Acrulia
1 Body wide (Fig. 1). Middle portion of head strongly elevated, with longitudinal ridges, reaching apical margins of ocelli. Postocular carina small, acute. Mesoventrite fully carinate (Fig. 21). Forebody yellow-brown to reddish-brown. Aedeagus as in Fig. 33–34. Body length: 1.70–2.60 mm. Europe, Central Asia, Siberia.............................. A. inflata (Gyllenhal)
- Body narrower, elongate (Figs. 2–4). Middle portion of head slightly elevated, with longitudinal ridges, reaching level of middle of eyes. Postocular carina lacking. Mesoventrite partially carinate. Coloration of body different................. 2
2 Body darker: head and abdomen brown, pronotum and elytra brownish-yellow; posterior two-thirds of elytra with distinct, large, brown spot (Fig. 4). Median lobe of aedeagus narrow, parameres extending beyond apex of median lobe (Fig. 37). Body larger: 2.20–2.70 mm. Greece ................................................ A. assingi Zanetti & Shavrin, sp.n.
- Body paler, yellow-brown; posterior third of elytra with indistinct, small, brown patch (Figs. 2–3). Median lobe of aedeagus moderately wider, parameres not reaching apex of median lobe (Fig. 35). Body smaller: 1.59–2.03 mm. Turkey ................................................................................................ A. akbesiana (Pic)