Asemum

Subfamily

Spondylidinae

Diagnosis - adult

Body length: 8–22mm.
Eyes: eye interommatidial setaeseta:
a sclerotized hair-like projection of the cuticle
present, eye entire/shallowly emarginateemarginate:
notched at the margin
, eye ommatidial density fine to coarse.
AntennaeAntenna:
in larval and adult insects, paired segmented appendages, borne one on each side of the head, functioning as sense organs and bearing a large number of sensilla
: antennal length barely surpassing pronotumpronotum:
the upper and dorsal part of the prothorax
or reaches between basebase:
the part of any appendage or structure that is nearest the body
and end of elytraelytron:
the leathery forewing of beetles, serving as a covering for the hind wings, commonly meeting opposite elytron in a straight line down the middle of the dorsum in repose
, antennal flagellar segments elongateelongate:
much longer than wide
, scapescape:
the first proximal segment of the antenna
smooth/punctate at apexapex:
end of any structure distad to the base
, antennal scapescape:
the first proximal segment of the antenna
≥ segment 3 or segment 3 > scapescape:
the first proximal segment of the antenna
.
Pronotumpronotum:
the upper and dorsal part of the prothorax
: pronotumpronotum:
the upper and dorsal part of the prothorax
shape transversetransverse:
broader than long
or subquadratesubquadrate:
not quite a square
, pronotumpronotum:
the upper and dorsal part of the prothorax
lateral armature absent.
Prosternum: prosternal process not dilated at apexapex:
end of any structure distad to the base
, procoxal cavities open posteriorly.
ElytraElytron:
the leathery forewing of beetles, serving as a covering for the hind wings, commonly meeting opposite elytron in a straight line down the middle of the dorsum in repose
: elytral length reaching or close to end of abdomen, elytral apicesapex:
end of any structure distad to the base
rounded or truncatetruncate:
cut off squarely at the tip
, elytral color black or brown, elytral color pattern absent.
Legs: visible tarsomeres: 4, femora robust, rarely slender, protibial spurs: 2, tarsal claws simple.

Head small; maxillary lobes reduced; eyes transversetransverse:
broader than long
, entire or feebly emarginateemarginate:
notched at the margin
, moderately finely faceted and pubescentpubescent:
downy; clothed with soft, short, fine, loosely set hair
; antennaeantenna:
in larval and adult insects, paired segmented appendages, borne one on each side of the head, functioning as sense organs and bearing a large number of sensilla
usually slender, filiformfiliform:
threadlike, i.e., slender and of equal diameter, being commonly applied to antennae
, much shorter than body in both sexes, eleventh segment appendiculateappendiculate:
bearing appendages
. Pronotumpronotum:
the upper and dorsal part of the prothorax
transverse, sides dilated, rounded or subangulate, disk moderately convex; prosternum with anterior margin flat; stridulating plate of mesonotum large, divided by channel; metepisterna moderately narrow, pointed apically. ElytraElytron:
the leathery forewing of beetles, serving as a covering for the hind wings, commonly meeting opposite elytron in a straight line down the middle of the dorsum in repose
parallel-sided, slightly convex; apicesapex:
end of any structure distad to the base
rounded. Femora moderately robust; anterior tibiaetibia:
the leg segment distal to the femur, proximal to the tarsus
armed with 2 spurs (Chemsak 1996Chemsak 1996:
Chemsak, J.A. 1996. Illustrated Revision of the Cerambycidae of North America. Volume I. Parandrinae, Spondylidinae, Aseminae, Prioninae. Wolfsgarden Books. Burbank, California 1: i-x + 1-150, pls I-X. ISBN 1-885850-02-6.).

Similar genera

Arhopalus, Tetropium

Differential diagnosis

Can be differentiated from Arhopalus by the paired protibial spurs, smaller eyes, and shorter antennaeantenna:
in larval and adult insects, paired segmented appendages, borne one on each side of the head, functioning as sense organs and bearing a large number of sensilla
. From Tetropium by the undivided pubescentpubescent:
downy; clothed with soft, short, fine, loosely set hair
eyes.

Distribution

temperate Holarctic

Recorded host plants

Pinaceae

Remarks

9 spp. (4 Old World + 4 New World, A. striatum holarctic)

Synonyms

Liasemum Casey, 1912

Taxonomy

Asemum Eschscholtz, 1830, Bulletin de la Société Impériale des Naturalistes de Moscou 2: 66.