Beetles Identification Guide

eyes larger and more convex, and the antennae longer (10th segment about five
times as long as wide). Females (as in Fig. 225) have the elytra subobovate, the
eyes smaller and less convex, and the antennae shorter (10th segment about twice
as long as wide).
Distribution: Almost cosmopolitan. In Canada adults of the diploid form have
been found in Nova Scotia, Quebec, Ontario, and British Columbia; females of
the triploid form have been collected in Montreal and Toronto.
Economic importance: The diploid form is found under natural conditions in
the nests of wasps, birds, and rats, as well as in warehouses. The triploid form has
been found mainly in warehouses, where it lives in close association with the bisexual
form. The females of the parthenogenetic form must mate with males of
the sexual form to reproduce or, less successfully, with males of P. pusillus and P.
fur. The sperm activates the egg but does not contribute any chromosomes.
This species has been recorded by Aitken (1975) on Canadian cargo ships carrying
wheat.
Ptinus fur (Linnaeus)
whitemarked spider beetle
ptine bigarré
Diagnosis: The species is distinguished from the other Ptinus included here in
having 2 tufts of setae on the pronotal disc, with the surface between the tufts
dull, punctured, and granulated.
Sexual dimorphism: Males (Fig. 224) have the elytra subparallel-sided, the eyes
larger and more convex, the antennae longer (10th segment about five times as
long as wide), the tufts of setae on the pronotal disc less defined, and the
metasternum longer and convex. Females (Fig. 225) have the elytra subobovate,
the eyes smaller and less convex, the antennae shorter (10th segment about
twice as long as wide), the tufts of setae on the pronotal disc more defined, and
the metasternum shorter and flat.
Distribution: Reported from Europe, North Africa, Asia, New Zealand, and
North America, where it was introduced before 1870. In Canada the species has
been collected in all provinces.
Economic importance: In Canada, this species is found mainly in warehouses
and dwellings, less frequently in museums, granaries, and grain elevators. It is
one of the most commonly reported ptinids in British Columbia.
Ptinus ocellus Brown (synonym: P. tectus auct.)
Australian spider beetle
ptine ocellé
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