The variegated mud-loving beetles (Coleoptera: Heteroceridae) of Mississippi and Alabama, with discussion and keys to the species occurring in the southeastern United States Author King, Jonas G. Author Lago, Paul K. text Insecta Mundi 2012 2012-12-28 2012 275 1 53 journal article 10.5281/zenodo.5188356 1942-1354 5188356 AC2597CC-301F-4E91-9711-5C17399C9AA2 18. Tropicus pusillus (Say) ( Fig. 26, 27 , 53 , 71 ) Heterocerus pusillus Say 1823: 200 . Tropicus pusillus (Say) : Pacheco 1964: 137 . Description. Length 2.3 - 3.0 mm. Orange-brown. Elytra orange laterally, with a common brown macula medially ( Fig. 26 ). Males with a process extending from the dorso-lateral edge of each mandible that wraps around the edge of the labrum ( Fig. 27 ), often nearly meeting the process from other side. Postmetathoracic coxal and post-mesothoracic coxal lines absent. Male genitalia ( Fig. 53 ) of the typical Tropicus type , dorsal edge projecting anteriorly. Diagnosis. Tropicus pusillus can be easily distinguished from all species of southeastern heterocerid by color pattern alone. The elytra are not trifasciate, as they are in southeastern Heterocerus , but have brown sutural margins. Together, these darker margins produce a rather even-edged median macula on the elytra. This coloration also easily distinguishes T. pusillus from its only southeastern congener, Tropicus nigrellus n. sp. , which is entirely black. Notes. Often the most numerous beetle at a UV light placed near a body of water in the southeastern U.S. , T. pusillus is the only species of heterocerid consistently collected from intermittent creek beds, drainage ditches, and sandy ponds. During this project, specimens were collected from the margin of a brackish marshy habitat on the campus of the Gulf Coast Research Laboratory in Ocean Springs, Mississippi . Distribution . Tropicus pusillus occurs from near the Canadian border south to Panama and Cuba . It was collected in all 63 Mississippi counties where UV lights were run as part of this project, as well as from most Alabama collection localities sampled by Harris et al. (1991 , Fig. 39 ). Specimens examined. 1802 (See Appendix).