Custotychus, Park and Wagner, 1962

Chandler, Donald S. & Geromini, Sarah D., 1962, A Revision of the Eastern Nearctic GenusCustotychusPark and Wagner, 1962 (Coleoptera: Staphylinidae: Pselaphinae), The Coleopterists Bulletin 1962 (2), pp. 217-242 : 217-242

KEY TO THE SPECIES OF CUSTOTYCHUS

The key is only to males. Females are very uniform in appearance and are best identified by association with males taken in the same collection event. Females tend to have fewer ocular facets than do males, sometimes markedly so, and can be identified on this basis for a local fauna where

2) C. chickasaw ; 3) C. daggyi ; 4) C. lobatus ; 5) C. turnbowi ; 6) C. rothorum ; 7) C. spinosus . Scale bars = 0.1 mm.

the pattern of male/female ocular numeration is known and differs between species. Females have not been associated with all species at this time. The two sexes are easily separated by the presence of the male metasternal tubercle, which is lacking in females. Nearctitychus sternalis is a species commonly sorted out as Custotychus and easily separated by the coarse punctures on the anterior portion of the vertex up to and including the antennal tubercles and the broadly rounded mesal margin of the third maxillary palpomere (Chandler 2000). The vertex is smooth, and the basal mesal margin of the third palpomere is rounded-angulate in Custotychus .

1. Metasternal tubercle arises at posterior margin of metasternum, curving anteriorly ( Figs. 20b, 21b ); genitalia with apices of lateral arms of dorsal plate bifurcate, median lobe elongate, margins parallel to truncate apex ( Figs. 6, 7 ); southeastern US states..................................................2

1′. Metasternal tubercle preapical to central on metasternal disc, erect to slightly angled posteriorly ( Figs. 17a , 28a ); genitalia different, rarely with lateral arms of dorsal plate bifurcate ( Figs. 4 , 8 ).........................3

Figures

Figs. 16–27. Custotychus species, scanning electron micrographs right lateral (a) and posterior (b) views of metasternal tubercle. 16) C. chickasaw; 17) C. daggyi; 18) C. lobatus; 19) C. turnbowi; 20) C. rothorum; 21) C. spinosus; 22) C. verticalis; 23) C. watrousi; 24) C. carloritaorum; 25) C. leei; 26) C. minor; 27) C. natchez. Grid for measurements of 20 or 50m at bottom of micrographs.

Figs. 1–7. Custotychus species. 1) C. natchez, dorsal habitus; 2–7) Aedeagus, dorsal and left lateral views:

Figs. 28–32. Custotychus species. 28) C. pocahontas, scanning electron micrographs of right lateral (a) and posterior (b) views of metasternal tubercle. Grid for measurements of 20 or 50m at bottom of micrographs; 29) C. carloritaorum, mesotibial spurs; 30) C. spinosus, mesotibial spurs; 31) C. watrousi, abdominal ventrites, ventrolateral view; 32) C. daggyi, right maxillary palpus, ventral view. Scale bar = 0.1 mm.

Figs. 8–15. Custotychus species, dorsal and left lateral view of aedeagus. 8) C. cavei; 9) C. verticalis; 10) C. watrousi;