Family Staphylinidae 
Rove Beetles 
This very large family has over 300 genera, several of which contain numerous 
species. Rove beetles occur commonly in eastern forests on, in or near the forest 
floor, or under bark of dead trees. Many species are conspicuous and easily 
recognized, though the family is difficult to define. Adults are usually elongate, 
slender beetles, small to medium in size, and can run with considerable speed. The 
wing covers of nearly all species are decidedly shortened, exposing a long and 
slender abdomen. When disturbed, many of the larger species turn the tip of their 
abdomen up and over the body, as if threatening to sting, as they run away. Most 
species are uniformly black or brown, but many have red or yellow body segments 
interspersed among the somber colors. A large species often: encountered, Phi- 
lonthus cyanipennis F., is iridescent blue, purple, or green. Rove beetle larvae are 
highly variable, and several distinct types occur from soft, white larvae to heavily 
sclerotized, black larvae. 
Most members of this family of beetles are predacious on insects or other similar 
soft-bodied small animals. A few species feed on fungi, a few on pollen, and some 
members of the genus Aleochara are known to be parasitic on fly pupae. Staph- 
ylinids are not economically important though many species occur in any given 
forest type. Common and conspicuous predacious genera that occur in a variety of 
forests are Staphylinus and Philonthus, which contain some of the largest members 
of this family. Other general predators are species of Quedius, Tachyporus, Medon, 
Lathrobium, and Astenus. 
Members of at least 20 different genera in the eastern regions are known to be 
predacious on bark beetle eggs and first instars, and small wood borer larvae. | 
Among those, the species of Nudobius, Quedius, Phloeopora, Atrecus, 
Olisthaerus, Charhyphus, Placusa, and Phloeonomus are common in eastern 
forests. Other genera contain species that can be predacious on insects under bark, 
such as Tachinus, Sipalia, Leptacinus, and Homaeotarsus. A few genera often 
occur in bark beetle galleries, but apparently do not feed on bark beetle eggs or 
larvae. Of these, members of the genus Afhefa are common, and sometimes also 
Siagonium. 
None of the staphylinid species is known to be a major factor in the control of any 
harmful forest pest. However, they are a consistent and abundant component of the 
complex forest ecosystems. 
Family Passalidae 
Passalid Beetles 
These beetles are discussed because of their interesting appearance and biological 
habits. Most species occur in the tropics. Of the three species recorded from the 
United States, only the horned passalus, Odontotaenius disjunctus (Illiger), has a 
very wide distribution in the Eastern United States. Adults are large, somewhat 
flattened, parallel-sided, shiny black beetles from 30 to 40 mm long. The thorax 
and abdomen are separated with a narrowed “waist.” The elytra are deeply grooved 
and a short, forward curved hook occurs on the top of the head. The three rigid, 
terminal antennal segments are widened into a loose club that cannot be rolled 
together. 
Larvae and adults live together in colonies in damp, decayed logs and stumps. 
The cream or dull-white larvae are fed wood that has been reduced to a pulp and 
treated with digestive secretions by their parents (499). Both adults and larvae have 
stridulatory organs. When disturbed, or for communication, adults rub together 
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