LIBRARY

COLEOPTERA 599
Family CURCULlONIDlE Leach 1817 (Cur-cu'li-on'i-dre, from the Latin
curcul£o, a weevil, a snout beetle). German, RUssler, Russelkafer. Weevils,
Snout Beetles.
Minute to large species characterized by the prolongation of the head with a
snout of variable length, width, and shape. Mostly hard, dull-colored or brilliant
metallic beetles; shining, smooth, rugose, sculptured, punctured or striated;
scaly or hairy; oval, elongated, cylindrical, robust, or long, slender, and even
ant-like in form. Head prognathous, globose, slightly Or greatly extended, and
with mouth parts at the end of the snout. Eyes prominent. Antennre straight,
geniculate, moniliform, clavate, 10- to 12-segmented and with three-segmented
club. Snout short and wide or long and decurved; may be grooved for reception
of the antennre. Mouth parts small, strong. Labrum present or absent. Mandibles
fiat, pincer-like, toothed on one or both sides. Palpi short and usually
concealed. Prothorax variable, narrow or as wide as mesothorax. Legs short or
very long, fore and middle coxre rounded, hind pair oval, fore coxal cavities
closed behind. Tibire sometimes armed. Tarsi five-segmented, simple or padlike,
fourth segment often very small. Claws, usually one pair or may be absent,
free or fixed. Wings well developed, rudimentary, or absent. Elytra usually
completely covering abdomen but may expose the pygidium. Abdomen with
five sternites, the first two fused.
Larvre curculionoid, i.e., robust, curved, with well.developed head, and
apodous. The body may be relatively smooth or wrinkled. Arboreal forms
may possess ambulatory process for moving and clinging. Secluded and subterranean
forms are pale whereas those exposed to the light are somber-colored
and frequently green, in most cases cryptic. The adults and larvre are phytophagous
and feed in or on almost every conceivable part of the plants as root borers,
leaf, root, fruit, and seed eaters and leaf miners. Pupation occurs in a cocoon
made of fibers of the host or of silk taken from the anus, or in cells in the ground.
The pupre are free. The life histories are variable and correspond in a general
way to those of other plant.eating forms. A complete life cycle may require
from 4 to 6 months to 1 or several years. All stages may hibernate and the adults
frequently also restivate.
The eggs are usually inserted into the plant tissues. The female first makes a
tubular hole, slit, or receptacle with the snout into which the eggs are thrust by
means of the elastic and ovipositor-like pygidium.
Parthenogenesis occurs in certain genera as in Brachyrhinus. No truly aquatic
forms are known although the larvre of many species live in the roots of plants
growing in bogs and marshes, and the adults may dive and swim under water.
The adults are nocturnal or diurnal and are usually slow walkers and fiiers,
but some forms are exceedingly quick on the wing during the heat of the day.
This is probably the largest family of insects and one of the largest groups of
closely related living things. It includes approximately 40,000 species which are
relegated to no less than 20 subfamilies according to modern workers. Of all the
groups of insects this is probably the most difficult to treat in a book of this
type since there are hundredB of interesting and important species that one