Gnathotrichus

Type species

Gnathotrichus corthyloides Eichhoff

Adapted from Wood 1982, p. 1155-1166

Diagnosis

Gnathotrichus is distinguished from other Corthylina by the convergentlyconvergently:
structures coming together at an extreme or apex
aciculateaciculate:
sketched lines which appear to have been scratched with a fine needle
frons, at least below the eyes level.

Description

Species in this genus range from 2.0 to 3.7 mm in length and are approximately 2.9 to 3.3 times as long as wide. Their color ranges from light brown to almost black. The pronotumpronotum:
the upper or dorsal surface of the first thoracic segment
is longer than wide with its anterior half finely asperateasperate:
of a surface or texture which is rough
and its anterior margin serrate. The scutellumscutellum:
a shield-like bony plate or scale, as on the thorax of some insects
is large and flushed with the elytraelytra:
the two external and hardened or sclerotized forewings of adult Coleoptera, often appearing leather-like in texture
. The declivitydeclivity:
the apical portion of the beetle elytra that slopes downward
is convex, often sulcatesulcate:
having narrow, deep furrows or grooves
or bisulcatebisulcate:
a structure that is grooved in two places, often contiguous at both sides of a central line
, with granulesgranules:
a small grain-like elevation
or pointed tuberclestubercles:
stiff, pointed, tapered processes on the surface of the integument, usually shorter than a spine
. The vestiturevestiture:
a surface covering of scales or setae on the body, wing, or other appendage
is rare and consists of short and light hair-like setaehair-like setae:
setae that are thin and similar to a hair
. The metepisternummetepisternum:
the sclerite between the first and second lateral thoracic sutures
is only visible anteriorly. The anterior margin of the compound eye is emarginateemarginate:
notched or indented
. The scapescape:
the first and basal segment of the insect's antennae
is longer than the 5-segmented funiclefunicle:
the antennal segments located between the scape and the club in some Coleoptera
, which appears as 4-segmented. 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 obovateobovate:
inversely egg shaped (ovate), with the narrow end basal
, has long setaesetae:
a hollow, often slender and hair-like cuticular projection
on females, and has from zero to three procurvedprocurved:
pertaining to structure (antennae, setae) which is basally perpendicular to the body and whose apical part is curved anteriorly
sutures. The procoxaeprocoxae:
extra segment occasionally preceding coxa (hip joint) of the first or anterior pair of legs of arthropods
are contiguouscontiguous:
sharing an edge or boundary; touching
.

Distribution

North and Central America

World fauna

Number of species: 16, Native species: 7, Introduced species: 0

Hosts

Abies, Alnus, Oreopanax, Picea,Pinaceae, Pinus, Populus, Pseudotsuga, Quercus, Tsuga