Diochini Casey 1906:
Diochus schaumi
Kraatz 1860

Figure 2.3.1 Diochus schaumi Kraatz, forebody. 10.1.1 D. schaumi, dorsal habitus. 10.1.2 D. schaumi, showing dark abdomen. 10.1.3 D. schaumi, in copula.


Diochus schaumi is distinctive among Staphylininae for its combination of a thin neck (about ¼ the width of the posterior head) (Fig. 2.3.1), broad and flattened pronotum, and elytra that do not overlap (Fig. 10.1.1). This species is variable in colour (Fig. 10.1.2).


This species is widely distributed in eastern and southern North America, but is not found west of the Rocky Mountains (Smetana 1982). Its distribution is distinctly south of the boreal forest region and is most typically found in forests with southern characteristics (Map 1).  Data from Map 1 includes localities found in Smetana (1982).

Eastern Canada: ON, QC
Adjacent U.S.: WI, MI, IN, OH, PEN, NY, NH, ME

Diochus schaumi has been collected in ECAS from March to December, with most individuals collected in April and May. However, copulation occurs in fall, as late as November (Fig. 10.1.3).


This species is frequently collected by sifting litter and other debris in wet areas including slough forests, swamps, marshes, and bogs. Smetana (1982) also reported it from the nests of Microtus pennsylvanicus (meadow vole) and from ‘debris at the base of grass tufts’.