Xystosomus parainsularis, Erwin, 1973

Erwin, Terry L., 1973, Studies of the subtribe Tachyina (Coleoptera: Carabidae: Bembidiini), Part I: A revision of the Neotropical genus Xystosomus Schaum, Smithsonian Contributions to Zoology 140, pp. 1-39 : 26

The parainsularis group

The members of the parainsularis group are characterized by similarities of the male genitalia, female genitalia, and pronotal structure. Externally, the forms appear to be diverse for two reasons: first, the body form of X. parainsularis is narrow while that of X. bisulcifrons is broad; second, the elytra of X. parainsularis are smooth while those of X. bisulcifrons are punctate. The result of these diversities is a superficially different appearance of the two species. Xystosomus parainsularis is similar in appearance to Tachymenis insularis (Darlington) while X. bisulcifrons is similar to a mix of gruti , inflatus , and microtretus group members. However, the male genitalia of the two species in the parainsularis group are very similar and would

fall between those of the gruti group and laevis group if placed in a morphocline.

There are two known species representing this group, one from Brazil and one from Colombia- Venezuela ( Figure 71 ).

Figures

FIGURE 71 Approximate ranges of the parainsularius group (crosshatched areas).