Weevils - Entomological Society of Canada

times longer than wide, twice as wide as pronotum; surface randomly
punctured, the punctures close and deep, with coarse, erect setae; striae
and interstriae inconspicuous.
Distribution. Saskatchewan to southern Ontario, south
throughout the entire United States. Manitoba: Aweme, Baldur,
Boissevain, Brandon, Onah, Pierson, St. Claude, and Whitewater.
Ontario: Windsor. Saskatchewan: Minton, Roche Percee, and
Stockholm.
Map 31. Collection localities of Haplarhynchiles a.eneus.
Comments. Adults of this species are easily recognized by the
generic characters summarized above; by the abundant, erect pubescence;
and by the dense, random punctures on the elytra. Hamilton (1973)
investigated the biolory of this species in northern lllinois. His
observations are probably valid in Canada. Male and female weevils are
usually observed together on sunflower heads shortly after their
appearance in July. Copulation takes place on these developing heads.
After (and even during) copulation the female weevils cut the stem just
below the developing heads. The cut is not complete and the flower head
is left hanging. Eggs are deposited within the base of the disk flowers of
the cut heads. Eggs hatch in about a week. The time between larval
instars is 20-30 days. The first-instar larvae feed on the pollen within
one disk flower. As the larvae grow to second and third instars, they
consume adjacent disk flowers. Up to three larvae may be found in a
single head. When mature, the larvae leave the cut heads and enter the
soil to a depth of about 30 cm. One generation occurs every year. In the
spring and early summer, larvae are found in the soil around the host
plants. Pupae are found in dirt cells in and around the roots in the first
week of July. Pupation takes about 10 days. Hosts include sunflower
(Helianthus species), rosinwood (Silphium species), Heliopsis species,
L70