Xenogonilla (Trechicus), LeConte, 1853

Bousquet, Yves, 2012, Catalogue of Geadephaga (Coleoptera, Adephaga) of America, north of Mexico, ZooKeys 245, pp. 1-1722 : 781

Subgenus Trechicus LeConte, 1853

Trechicus LeConte, 1853c: 386. Type species: Trechicus umbripennis LeConte, 1853 (= Bembidium nigriceps Dejean, 1831) designated by Jeannel (1926: 247). Etymology. From the generic name Trechus [q.v.] and the Greek eicon (image, figure), probably alluding to the resemblance of the adults to those of Trechus ("have very much the appearance of minute Trechus") [masculine].

Extromus Péringuey, 1896: 584, 586. Type species: Extromus pusillus Péringuey, 1896 (= Bembidium nigriceps Dejean, 1831) by monotypy.

Diversity.

Eighteen species in the Nearctic (one endemic species), Australian (seven endemic species), and Afrotropical (ten endemic species) Regions and one ( Perigona nigriceps ) subcosmopolitan species.

Identification.

Bousquet (1987a: 128) commented on the structural differences between the two species found in North America.

Taxonomic Note.

Hirtoperigona Perrault is placed in synonymy with Trechicus in Lorenz (2005: 438). However, the position of the median group of setae of the umbilical series in the type species ( Perigona tronqueti Perrault from Sri Lanka) and in Perigona pubescens Jeannel (from Vietnam) suggests that members of Hirtoperigona are more closely related to Perigona s.str. than to Trechicus . Perrault (1988) placed a third species ( Perigona hirtella Basilewsky from Africa) in Hirtoperigona on the basis of the original description alone; according to Basilewsky (1989: 447), the species belongs to Trechicus .

The relationship of the endemic North American species ( Perigona pallipennis LeConte) has not been studied and, in my opinion, it may be more closely related to members of Cryptoperigona than to those of Trechicus .