Beetles Identification Guide

the Coleoptera dealt with here by their general habitus (Figs. 190 and 191), particularly
their small, depressed body and the presence of a carina, which is parallel
to the lateral margin, on the pronotum. Cryptolestes ferrugineus differs from
the two other species of the genus discussed here in having the carina on the head
not extended transversely near the posterior margin. Both this species and C.
pusillus have 4 rows of setae on the second elytral interval.
Sexual dimorphism: Males have the mandible expanded laterally near the base
(Fig. 246) and 4-segmented hind tarsi. Females have the mandible not expanded
at base (Fig. 246) and 5-segmented hind tarsi. Unlike C. pusillus and C. turcicus,
the length of the antennae is not sexually dimorphic in C. ferrugineus.
Distribution: Cosmopolitan. In Canada the species occurs from coast to coast.
Economic importance: This species is the most serious pest of stored grain, particularly
wheat, in Canada (Watters 1955; Sinha 1961). According to Rilett
(1949), C. ferrugineus became a major pest of stored grain in western Canada
during the years 1939—1944. It is found mainly in granaries, grain elevators,
and mills, where both adults and larvae feed almost exclusively on the germ of
the grain kernel. In tropical and subtropical regions it also infests oilseeds and
cocoa beans (Howe and Lefkovitch 1957).
Cryptolestes pusillus (Schonherr) (synonym: C. minutus Olivier)
flat grain beetle
cucujide plat
Diagnosis: The species differs from C. ferrugineus in having the carina on the
head extended transversely near the posterior margin and from C. turcicus in
having 4 rows of setae, instead of 3, on the second elytral interval and the carina
on the head stronger.
Sexual dimorphism: Males have the antennae extended to about four-fifths of
the length of the body (see Fig. 190) and 4-segmented hind tarsi. Females have
shorter antennae, extended to about half the length of the body (see Fig. 191),
and 5-segmented hind tarsi.
Distribution: Recorded from many countries but more common in wet tropical
and warm temperate regions. In Canada the species has been reported from
Quebec west to British Columbia, but some of these records could have resulted
from misidentification of C. turcicus. The species can survive Canadian winter
conditions only in a heated environment.
Economic importance: The flat grain beetle is probably the least damaging
Cryptolestes species in Canada. It is found mainly in grain elevators and flour
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