(Figs. 1–6)
Milichilinus Reitter, 1908 was described as a subgenus of Xantholinus Dejean, 1821 for the species decorus Erichson, 1839 and ever since has been considered a subgenus (Herman 2001). Although similar externally to Xantholinus, Milichilinus differs in having a maxillary palpus with short terminal segment only slightly narrower than segment 3 which, in turn, is longer than segment 2 (Fig. 1), a similarly-shaped labial palpus (Fig. 2), a short labrum with externally extended lobules and a narrow median V-like emargination (Fig. 3), very faint frontal and ocular grooves, a medially sclerotized and laterally impressed antesternal plate and, finally, feebly dilated anterior tarsi.
It is also distinguished by the shape of the male genital segment which has distally dilated pleurites, a predominantly filiform tergite X (Fig. 4), sternite IX almost totally covered with very long dense spinules, conditions not found in any other Xantholininae (Fig. 5). In the genus Xantholinus the aedeagus has no parameres (reduced to vestiges). In Milichilinus the aedeagus has large, very long semimembranous and asymmetrical parameres (Fig. 6). Illustrations of stenite IX and the aedeagus of both Milichilinus species are provided by Assing (2006).
In light of the above, I consider Milichilinus to be a distinct genus which presently includes two species: M. decorus (Erichson, 1839) (the type species, by monotypy) [see Smetana (2004) for its distribution] and M. meybohmi Assing, 2006 from Turkey (Kahramanmaraş).
The illustration in Coiffait (1972: Fig. 84, A) probably refers to M. decorus, but it is apparently based on an aedeagus with the parameres removed in the process of dissection.
Based on the shape of the aedeagus (especially the large, asymmetrical and semimembranous parameres) Milichilinus is the only Palaearctic xantholinine with affinities to Oriental genera, such as Sumatera Bordoni, 2002 or Atopolinus Coiffait, 1982 (Bordoni 2002).
From this follow the resulting new combinations:
Milichilinus decorus (Erichson, 1839), comb. nov.
Milichilinus meybohmi (Assing, 2006), comb. nov.
FIGURES 1–6. Milichilinus decorus (Erichson): maxillary palpus (1), labial palpus (2), labrum (3), male genital segment (4), sternite IX (5), aedeagus (6).