Most of the dominant families - such as the Carabidae (ground-beetles), Scarabaeidae (chafers), or Curculionidae (weevils) have a distribution as wide as the order.
In the Triassic rocks of Switzerland remains of weevils (Curculionidae) occur, a family which is considered by many students the most specialized of the order.
Horn placed the Rhynchophora (weevils) in a group distinct from all other beetles, on account of their supposed primitive nature.
Kolbe, on the other hand, insists that the weevils are the most modified of all beetles, being highly specialized as regards their adult structure, and developing from legless maggots exceedingly different from the adult; he regards the Adephaga, with their active armoured larvae with two foot-claws, as the most primitive group of beetles, and there can be little doubt that the likeness between larvae and adult may safely be accepted as a primitive character among insects.
The Curculionidae, or weevils (q.v.), comprising 23,000 species, are by far the largest family of the group. The maxillary palps are short and rigid, and there is no distinct labrum, while the feelers are usually of an "elbowed" form, the basal segment being very elongate (figs.
3) of some weevils live in seeds; others devour roots, while the parentbeetles eat leaves; others, again, are found in wood or under bark.
In all climates fruit and forest trees suffer from weevils or Curculionidae.
In Europe a number of " long-snouted " beetles, such as the raspberry weevils (Otiorhynchus picipes), the apple blossom weevil (Anthonomus pomorum), attack fruit; others, as the " corn weevils " (Calandra oryzae and C. granaria), attack stored rice and corn; while others produce swollen patches on roots (Ceutorhynchus sulcicollis), &c. All these Curculionidae are very timid creatures, falling to the ground at the least shock.
Larval " weevils " mostly feed on the roots of plants, but some, such as the nut weevil (Balaninus nucum), live as larvae inside fruit.
Seeds of various plants are also attacked by weevils of the family Bruchidae, especially beans and peas.
The corn weevils (Calandra granaria and C. oryzae) are now found all over the world, in many cases rendering whole cargoes of corn useless.
The occurrence of weevils - among the most specialized of the Coleoptera - in Triassic rocks shows us that this great order of metabolous insects had become differentiated into its leading families at the dawn of the Mesozoic era, and that we must go far back into the Palaeozoic for the origin of the Endopterygota.
(Cattle food.) The adult weevils puncture the young flower-buds and deposit eggs; and as the grubs from the eggs develop, the bud drops.
Among other things Hales invented a "sea-gauge" for sounding, and processes for distilling fresh from sea water, for preserving corn from weevils by fumigation with brimstone, and for salting animals whole by passing brine into their arteries.
Thus he showed that the weevils of granaries, in his time commonly supposed to be bred from wheat, as well as in it, are grubs hatched from eggs deposited by winged insects.
In the Philippine Islands several species of Longicorns of the genus Doliops mimic hard inedible weevils (Curculionidae) of the genus Pachyrhynchus.
The antennae of these weevils are short and end in a knob; those of the Longicorns are very much larger, but the weevil-like look is produced by the presence of a knob-like swelling upon the third joint, the terminal portion of the antenna being so extremely fine as to be almost invisible.
The branches are some times attacked by weevils (Rhyn- cites) and the larvae of various moths, and saw-flies (chiefly Erio- campa) feed on the leaves, and young branches and leaves are sometimes invaded by Aphides.
The Rhyncophora embrace four families, - (1) the Curculionidae, or true weevils, (2) the Scolytidae, or bark:.
In an unobtrusive way weevils do immense harm to vegetation.
Many of them devour seed, as the corn weevils, Calandra granaria and C. oryzae, and in this way vegetation is severely injured, and its spread seriously checked.
The Bruchidae are often called "weevils," but they have no close affinity with the Rhynchophora, being nearly allied to the Chryso - melidae or leaf beetles.
Insect life is somewhat less remarkable; but besides a distinctive genus of Orthoptera (Jaquetia Hospodar), there are several kinds of weevils (Curculionidae) said to be peculiar to Rumania.