Weevils - Entomological Society of Canada

Trigonorh i n u s an n u I atu s (Carr)
Brachytarsus annulatus Carr, 1930:279 (holotype, Medicine Hat,
Alta.;CNC).
T rigonorhinu s annulatus : Valentine 7957 :9 ; Valentine 1960 : 58, 80 ;
Valentine 1971:245.
Description. Length 3.2-3.7 mm (head excluded). Integument of
head, pronotum, and elytra dark reddish brown to almost black.
Pubescence consisting of white and brown setae; setae on elytra silvery
with numerous brown spots, with larger spot on base and at middle;
setae on pronotum white and brown intermixed or white and forming at
least traces of 3 longitudinal stripes; pubescence on tibiae annulate or
spotted, with 2 dark and 3 pale areas; each abdominal sternite often with
a lateral spot of brown setae. Frons weakly and transversely impressed
just below eye level, weakly convex above; surface densely punctured,
the rims of punctures elevated. Rostrum moderately prolonged; surface
as on frons. Pronotum 1.1 times wider than long, widest at basal angles;
sides weakly arcuate, converging to narrowly rounded anterior margin;
disc evenly convex, weakly impressed before basal carina; surface
densely punctured, the rims of punctures slightly elevated; basal carina
weakly emarginate, acutely elevated. Elytra about 1'4 times longer than
wide; sides weakly arcuate to broadly rounded apex; disc evenly convex;
striae moderately impressed in even rows; interstriae flat, densely and
finely punctured, about 4.0 times wider than striae.
Distribution. Alberta and British Columbia, south to Oregon
and Utah. Alberta: Medicine Hat. British Columbia: Osoyoos.
Comments. This species is rarely encountered. Adults can be
recognized by the densely punctured pronotal disc, on which the surface
between the punctures is elevated in what appear to be short, irregular
rugae, and by the color pattern previously described. Nothing is known
of the life history or habits of the species, except that specimens have
been collected on fungus-infected sagebrush (Artemisia species).
Tr i go n o rh i n us a/ternatus (SaY)
Map 6
Anthribus alternatus Say, 1826:250 (no type locality given; type
destroyed).
Brachytarsus q.lternatus: Blatchley and Leng 1916:38.
Brachytarsoides alternalus: Pierce 1930:30.
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