Weevils - Entomological Society of Canada

conspecific. This is the first record of A. hookeri in North Amerrca.
Freese (1981) described the biology of A. hookerl. Field and laboratory
data confirm that this species is monophagous on M. p erforata. Eggs are
laid in developing flowerheads; apical flowerheads appear to be prefered
over nonapicil ones. About 4to Slarvae are found per flowerhead and
each larva requires about 21 seeds for complete development. In one
study area in Europe, only about 357o of the seeds in a flowerhead are
used because of a high level of larval mortality resulting from
parasitoids. Similar data for Canadian conditions are unavailable.
Adults of this species can be recognized by the simple male tibiae, by the
lack of any color pattern on the elytra, by the lack of a tubercle on the
male metasternum, by the lack of a basal flange on the male pronotum,
and by the simple tarsal claws. Apion hookeri is placed in the subgenus
Omphalapion (Lohse 1981) and is the only North American
representative of that subgenus.
Apion huron Fall
Figs. 98, 99; Map 19
Apion huron Fall, 1898:159 (lectotype, Detroit, Mich.; MCZ);
Kissinger 1968:243; O'Brien and Wibmer 1982:24.
Description. Length 7.7-2.3 mm. Body moderately slender,
black; antennae with base and club paler. Pubescence consisting of
white, conspicuous setae; setae of male coarser and denser on lateral
areas. Frons wider than dorsal tip of rostrum, generally flat, rarely
slightly impressed near eye. Rostrum of male slightly curved, I'lI'2
times longer than pronotum; sides, in dorsal view, converging to apex,
not expanded at antennal insertion; sculpture and pubescence as in
A. cauifrons. Rostrum of female moderately curved, 1.2-1.3 times longer
than pronotum; sides, in dorsal view, nearly parallel in apical half
converging slightly beyond antennal insertion to tip; surface below
antennal insertion coarsely alutaceous, with sparse, minute vestiture;
surface above antennal insertion nearly smooth with minute punctures.
Antennae inserted between basal 0.3-0.4 (male) or at basal 0.3 (female)
of rostrum. Eyes moderately prominent. Pronotum at base I.l-L.z
times wider than long; sides lacking basal flange; apex slightly
constricted; disc nearly flat, with deep punctures; interpuncture spaces
alutaceous. Elytra 1.2-1.3 times longer than wide; striae deeply
impressed, with coarse punctures; interstriae more than twice as wide as
striae, nearly flat, each interstria with 1 row of scales; interstria 7 with 1
specialized seta. Metasternum of male with 1 median low tubercle near
posterior margin.
115