(Figs. 1 C, 2 C, 2 D, 3 D–F, 8)
Microphorus praecox Loew, 1864: 47.
Microphorella praecox (Loew): Becker, 1909: 28.
Type material examined. LECTOTYPE 3 (designated by Chvála, 1983) from Polish Silesia (as “Schlesien”), Poland, labelled: “Karlowitz/ 10.5.[18] 46.”; [small square purple label]; “ Microphorus / praecox / m.”; “ 10570 ”; “ Lectotypus ” [red label]; “Zool. Mus./ Berlin” [pale green label] (ZMHB) . PARALECTOTYPES: POLAND: 13, 2♀, with same data as lectotype (ZMHB); 13, Posen, 1.V. 1841, H. Loew [lacking red paralectotype label] (ZMHB); 1 ♀, same data except 14.V. 1842 [lacking red paralectotype label] (ZMHB) (see Remarks).
Other material examined. SWITZERLAND: Valais: 13, 2♀, Leuk-Pfynwald, Rhône- Kiesbett, 16.V. 2000, H. Ulrich (ZFMK, in ethanol); 13, 1♀, Leuk-Pfynwald, 27.V. 1999, B. Merz (MHNG, in ethanol); 13, 1♀, same data (CNC, critical-point dried and mounted on pins from ethanol).
Diagnosis. Microphorella praecox (Loew) is a medium-sized species for the genus (body length 1.2 –2.0 mm), shining white when dry and with white setae, with long pointed antennae, which most closely resembles M. similis (see ‘Comparison’ section of M. similis above for a list of characters shared with M. praecox and those differing from it). It is distinguished from other Microphorella species by the following combination of features: postpedicel (Fig. 1 C) elongate, roughly conical; stylus (Fig. 1 C; see also Chvála 1988, fig. 4) claw-shaped, curved ventrad and pointed, distinctly shorter than postpedicel; male mid leg with tarsomere 1 bowed and bearing a ventral comb-like row of hook-like setae (cf. Fig. 4 B); wing venation (Figs. 3 D, 3 F) with R 4 + 5 and M 1 straight, cell r 2 + 3 not narrowing before apex; M 2 and M 4 weakly divergent beyond cell dm, costal section between M 1 and M 2 only slightly longer than section between M 2 and M 4; hypopygium with ventral epandrial process Y-shaped with ventral arm of furca slender and curved with hump-like projection at base (Fig. 8 A), left postgonite lobe (Fig. 8 A) with pointed apex, phallus with longitudinal serration and lacking pointed process near middle (Figs. 8 A, 8 C); female terminalia (cf. Fig. 7) with acanthophorite setae, sternite 8 with apex narrow and bifurcate, cercus rounded and setose.
Redescription. Microphorella praecox was redescribed and illustrated in detail by Chvála (1988, figs. 4, 15, 16–18). The following redescription includes supplemental details in light of the discovery of the closely related M. similis. Male: Body length 1.2–1.6 mm, wing length 1.4–1.6 mm. Head (Figs. 1 C, 2 C): Similar to M. similis except: face about 1.5–1.6 X width of anterior ocellus, fronto-orbital bristles situated somewhat more anterior to posterior ocellus; antenna (Fig. 1 C; see also Chvála 1988, fig. 4) with postpedicel about 4 X longer than wide, broad basal portion about 1 / 2 length of narrow distal portion; stylus claw-shaped, 1 / 4 – 1 / 3 length of postpedicel. Thorax: Similar to M. similis. Legs: Similar to M. similis. Wing (Figs. 3 D, 3 E): Similar to M. similis except: cell r 2 + 3 not distinctly narrowing before apex; R 4 + 5 and M 1 straight, diverging apically; M 2 and M 4 weakly divergent beyond cell dm; costal section between M 1 and M 2 only slightly longer than costal section between M 2 and M 4. Abdomen: Similar to M. similis except: Hypopygium (Fig. 8): Ventral epandrial process (Fig. 8 A) with broader apical furcation, ventral arm slender and curved with hump-like projection at base; dorsal lobe of left surstylus (Fig. 8 A) with slender medial lobe rounded apically, not shallowly furcate; ventral lobe of left surstylus with similar complex multilobate medial projection (cf. Fig. 6 C); basal portion of right epandrial lamella with dorsal emargination slightly less pronounced (Fig. 8 C); apical portion of left postgonite lobe (Figs. 8 A, 8 C) with complex cuticular projections medially, apex narrow, pointed, not bifurcate; phallus (Figs. 8 A, 8 C), with longitudinal serration, lacking pointed process near middle, with short pointed preapical process present; right cercus (Fig. 8 B) with basilateral portion less developed.
Female: Body length 1.8 –2.0 mm, wing length 1.4–1.7 mm. Similar to male except as follows: Head (Fig. 2 D): Face about 1.7–2.3 X width of anterior ocellus; antennal stylus length from little more than half to 2 / 3 length of postpedicel; postpedicel with broad basal portion about equal in length to narrow distal portion. Legs: Foreleg: Femur without row of erect posteroventral setae; tibia without posterior and ventral rows of erect setae. Midleg: Femur without row of long erect posteroventral setae; tarsomere 1 not bowed, without strong basiventral setae, without ventral comb-like row of hook-like setae. Wing (Fig. 3 F): Costal setae proximal to apex of R 1 not enlarged and widely spaced. Abdomen: Terminalia similar to that of M. similis (cf. Fig. 7).
Distribution. Microphorella praecox occurs in central and northern Europe and has been recorded from the Italian mainland, Switzerland, Germany, Slovakia, Hungary, Poland, Finland and northwestern Russia (Zelenegorsk) (Chvála 1988, 1989, 2011). As noted by Chvála (1988), the record of this species from the Ostrobottnia borealis (ObS) region of Finland by Krogerus (1932) cannot be confirmed because the material has been lost. Some of the distribution records of M. praecox may actually refer to M. similis and need to be validated.
Remarks. Adults of Microphorella praecox are known to occur on sandy river banks from April to June in Central Europe (Chvála 1983, 1988; Shamshev & Grootaert 2004). The Swiss material from 1999 and 2000 listed above was collected (along with specimens of M. similis) by sweeping above gravel in the floodplain of the Rhône River in May.
Chvála (1983, 1988) considered the male paralectotype collected on 1.V. 1841 and the female paralectotype collected on 14.V. 1842 to be from Karlowitz (= Karlowice Wielkie NE of Nysa, Poland). However, it seems more likely that these two specimens are the paralectotypes from Posen (Poznań) that Chvála (1983, 1988) considered to be lost. Both specimens lack locality labels, an indication of material that was collected by Loew at his home, in Posen (J. Ziegler, pers. comm., December, 2011).