Beetles Identification Guide

Diagnosis: The species differs from the other Ptinus dealt with here in having the
elytral surface completely obscured by the vestiture, which consists mainly of
dark golden appressed setae. Superficially, this species is most similar to Niptus
hololeucus and Trigonogenius globulus, which also have the elytral surface completely
obscured by the vestiture; adults of P. tectus are distinct, however, in having
the area between the antennal insertions narrow instead of wide.
This species is known outside North America by the name Ptinus tectus
Boieldieu. However, under article 72C(e) of the new International Code of Zoological
Nomenclature, the valid name for the Australian spider beetle is Ptinus
ocellus Brown, since P. tectus Boildieu was originally proposed as a replacement
name for Ptinus pilosus White (= Dorcatoma pilosus White, an anobiid).
Sexual dimorphism: Sexes are externally similar, unlike the other species of Ptinus
dealt with in this guide.
Distribution: Originally from Tasmania and, outside the Australian region, known
to be established in Europe and North America. Records of cargo ships obtained
by Aitken (1975) in England suggest that the species may also be established at
high altitudes in the tropics. In Canada P. ocellus ranges from coast to coast.
Economic importance: This species is commonly found in warehouses in the
eastern provinces and in British Columbia. In the Prairie Provinces, it seems less
common and has been found only in grain elevators and flour mills.
Ptinus raptor Sturm
eastern spider beetle
ptine oriental
Diagnosis: The species is readily separated from the other Ptinus studied here in
having 2 tufts of very dense setae on the pronotal disc, with the surface between
the tufts shiny and smooth.
Sexual dimorphism: Males (as in Fig. 224) have the elytra subparallel-sided, the
eyes slightly larger and more convex, the antennae longer (10th segment about
five times as long as wide), and the metasternum longer and convex. Females (as
in Fig. 225) have the elytra subobovate, the eyes slightly smaller and less convex,
the antennae shorter (10th segment about twice as long as wide), and the
metasternum shorter and flat.
Distribution: Europe and introduced in North America. In Canada the species
ranges from coast to coast.
Economic importance: According to Gray (1941), P. raptor is the most common
Ptinus in eastern Canada. It occurs mainly in cereal products in warehouses.
164