Weevils - Entomological Society of Canada

to slightly constricted apex, without basal flange; disc slightly convex,
with deep punctures bearing coarse scales; interpuncture spaces
smooth, much narrower than diameter of punctures. Elytra 1.6 times
longer than wide; striae fine, moderately deep; interstriae variable in
width, narrowed toward base, convex, smooth; interstriae 1 and 2 with
1 irregular row of fine scales; interstria 3 with 2 or 3 rows of coarse
scales; interstriae otherwise generally with 1 row of moderately coarse
scales; interstria 9 with 1 long specialized seta. Tibiae of male all
mucronate.
Distribution. Manitoba to Alberta, south through the central
and southwestern United States to Baja California and Texas. Alberta:
Medicine Hat and Scandia. Manitoba: Boissevain. Onah. and Pierson.
Saskatchewan: Oxbow Pike Lake. and Roche Percee.
Map 25. Collection localities of Apion tenuirostrutn (O) and. Podapion Sahicotn, (O).
Comments. This species is a member of the subgenus
Trichapion.It is distinguished from other members of the subgenus by
the lack of a distinct basal flange on the pronotum and by the coarse
white scales on the elytra, which are denser on interstriae 3. This species
consists of at least three distinct populations, all of which occur in
southwestern Manitoba. In the typical A. tenuirostrum, the pronotum
at the base is very slightly longer than wide, and specimens range in size
from 2.1 to 2.3 mm. In a second population, the pronotum at the base is
as wide as or slightly wider than long, and the specimens are slightly
smaller than those of typical A. tenuirostrum, rangjng in length from
L.9 to 2.3 mm. A third population differs in that the pronotum at the
base ranges from 1.1 timei to 1.2 times as wide as long and adults are
distinctly smaller, rangingfrom 1.5 to 1.8 mm in length. The exact status
of these three populations is as yet unknown; determination must wait
for detailed biological studies. Adults have been collected from purple
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