Center for Systematic Entomology, Gainesville, Florida


Date of this Version



Eger JE Jr. 2020. A new species of Diolcus Mayr (Hemiptera: Heteroptera: Scutelleridae: Pachycorinae) with a reexamination of the subfamily and generic placement of Nesogenes boscii (Fabricius) (Hemiptera: Heteroptera: Scutelleridae: Elvisurinae or Pachycorinae). Insecta Mundi 0843: 1–11.

Michael C. Thomas Festschrift Contribution


Copyright held by the author(s). This is an open access article distributed under the terms of the Creative Commons, Attribution Non-Commercial License,

Published on December 25, 2020 by Center for Systematic Entomology, Inc. P.O. Box 141874 Gainesville, FL 32614-1874 USA


Diolcus thomasi Eger new species (Hemiptera: Heteroptera: Scutelleridae: Pachycorinae), is de­scribed from Cayman Brac and Little Cayman Island and compared to D. chrysorrhoeus (Fabricius), its closest congener. Nesogenes boscii (Fabricius) is removed from the Elvisurinae and placed in the Pachycorinae. The relationship of N. boscii to D. thomasi and D. chrysorrhoeus is discussed.

Diolcus Mayr (Hemiptera: Heteroptera: Scutelleridae: Pachycorinae) currently contains six valid species: D. cassi­doides (Walker) from Hispaniola, D. chrysorrhoeus (Fabricius) from the southeastern US and Texas, D. disjunctus Barber from Puerto Rico, D. irroratus (Fabricius) from Florida and many of the Caribbean Islands, D. pusillus Berg from Argentina and Uruguay, and D. variegatus (Herrich-Schaeffer) from Cuba, Hispaniola, Jamaica and adventive in Florida (Eger and Baranowski 2002). There has been little work on this genus recently and it is in need of revision.

Horváth (1921) removed Diolcus boscii (Fabricius) from Diolcus and placed it in a new genus, Nesogenes Horváth. He also placed the new genus in Elvisurinae based on the expanded lateral carinae of the thoracic sterna. The placement of N. boscii in the Elvisurinae has been challenged in recent years. Cassis and Vanags (2006) considered the genus incertae sedis and excluded it from the Elvisurinae. Eger et al. (2015) suggested that Nesogenes is more closely related to genera of Pachycorinae than to those of Elvisurinae. However, the subfamily placement of the genus remains unsettled.

The purpose of this study is to describe a single new species of Diolcus and clarify the subfamily placement of Nesogenes. This paper is dedicated to the memory of Mike Thomas, a good friend and avid collector of insects, particularly on Caribbean Islands.