Scolytus

Type species

Bostrichus scolytus Fabricius

Adapted from Wood 1982, p. 419-450

Diagnosis

The most distinctive character used to distinguish Scolytus from the similar genus Cnemonyx Eichhoff is the absence of a declivitydeclivity:
the apical portion of the beetle elytra that slopes downward
, which is reduced in Cnemonyx.

Description

Species in this genus range from 1.5 mm to approximately 5.2 mm in length and have a body size ratio of 2.0 to 2.4 times long as wide. Their color varies from dark reddish brown to almost black and shows transverse bands in some species. The pronotumpronotum:
the upper or dorsal surface of the first thoracic segment
is proportionally large in relation to its body and has the margins marked by a raised line; it usually appears as long as wide but it actually varies slightly. The scutellumscutellum:
a shield-like bony plate or scale, as on the thorax of some insects
is large. There is no declivitydeclivity:
the apical portion of the beetle elytra that slopes downward
and the abdomen can be seen ascending towards its apex. The anterior margin of the compound eye is sinuatesinuate:
descriptive of a narrow and winding thin structure or margin of a feature
to slightly emarginateemarginate:
notched or indented
. The scapescape:
the first and basal segment of the insect's antennae
is shorter than the 7-segmented funiclefunicle:
the antennal segments located between the scape and the club in some Coleoptera
. The clubclub:
the apical segment of the insect antennae that is enlarged or thickened such that it is anatomically differentiated from the preceding segments
is oval to obovateobovate:
inversely egg shaped (ovate), with the narrow end basal
, usually pubescentpubescent:
covered with closely set setae
, and can have one procurvedprocurved:
pertaining to structure (antennae, setae) which is basally perpendicular to the body and whose apical part is curved anteriorly
suture at most. Their procoxaeprocoxae:
extra segment occasionally preceding coxa (hip joint) of the first or anterior pair of legs of arthropods
are subcontiguoussubcontiguous:
pertaining to adjacent structures, margins, or surfaces that are in contact but are not united or fused
. The tibiatibia:
the fourth division of an insect's leg, between the femur and the tarsus
has a single apicalapical:
situated at the apex or extreme outer edge of a structure or appendage
spine.

Distribution

Most of the Northern Hemisphere and South America

World fauna

Species number: 120, Native species: 16, Introduced species: 4

Established exotic species

Scolytus mali is present in New York, New Jersey, Maryland, and Ohio.

Scolytus multistratus and Scolytus rugulosus are present in the entire continental United States and Alaska.

Scolytus schevyrewi is present in California, Oregon, Idaho, Utah, Nevada, Arizona, Montana, Wyoming, Colorado, New Mexico, Oklahoma, Kansas, Nebraska, South Dakota, Minnesota, Missouri, Illinois, Michigan, Indiana, Maryland, and New Jersey.

Hosts

Abies, Carya, Celtis, Cydonia, Crataegus, Fagus, Inga, Larix, Malus, Picea, Prunus, Pseudotsuga, Pyrus, Ulmus, Tsuga