Weevils - Entomological Society of Canada

The families treated herein, with the exception of Platypodidae, are
generally regarded as more primitive than Curculionidae. Some, especially
Nemonychidae, are known from pre-Cretaceous fossils, which differ
little from extant taxa. The families treated in this part represent only a
small fraction of the weevils of Canada and Alaska-only 90 species,
compared with the estimated 600 species in Curculionidae, which will be
treated in the next two volumes of this study.
Anatomy
The anatomical terms used in this book should be familiar to those
who study Coleoptera. Detailed defrnitions of terms can be found by
consulting Webster's Seuenth New Collegiate Dictionory, Nichols and
Schuh (1989), or the glossary at the end of this book. Most of the features
used in this work are illustrated in Fig. 14.
The following discussion is not intended to be a complete treatment
of curculionoid anatomy. It merely explains certain structural features
that may be of use in interpreting the keys or the descriptions. It
includes only those conditions that exist in the families treated herein.
Head. The head is usually conical or globular, with an elongate
rostrum extending in front of the eyes. The mouthparts are located at
the tip of the rostrum. The rostrum (called the beak by some authors)
varies in length, width, and structure. It is absent in Platypodidae;
broad and flattened in Anthribidae (Figs. 27-29); rather slender and
cylindrical in Apionidae (Fig. 6); stout and short in Ithyceridae; strongly
sexually dimorphic in Brentidae, in which it is straight and cylindrical
with minute mandibles in the female (Fig. a6) and flattened and broad
with prominent mandibles in the male (Fig. 45); short and muzzle-like,
widening beyond the antennal insertions in Attelabidae (Fig. 11);
slender and parallel-sided from the base to the antennal insertions
and widened and depressed beyond the antennal insertions in
Nemonychidae (Figs. 42,44); and parallel-sided or widened apically and
strongly arcuate to nearly straight in Rhynchitidae (Figs. 146,I49,I54,
155). Laterally the rostrum bears the antennae; the rostrum is usually
grooved to receive the scape ofthe antenna, and this groove, which is
short in most taxa treated herein, is called the scrobe. The antennae are
straight in most families but geniculate or elbowed in Nanophyes
(Fig. 19) and Platypodidae (Figs. \2, L3). Each antenna has 11
segments; the terminal three are usually enlarged, forming a more or
less distinct club (Figs. L5,17,18). The eyes are round or oval, flat to
strongly convex, sometimes notched opposite the antennal insertion.
The mouthparts are difficult to observe and are therefore not
extensively used in diagnosis. In some instances, however, the
mandibles offer valuable diasnostic characters. The mandibles of
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