Although in the case of the majority of Diptera the body is more or less clothed with hair, the hairy covering is usually so short that to the unaided eye the insects appear almost bare; some forms, however, such as the bee-flies (Bombylius) and certain robber-flies (Asilidae) are conspicuously hairy.
He flies to Persia, evades the pursuers whom Astyages sends after him, and begins the rebellion.
Of Neuroptera there are but few injurious species, and many, such as the lace wing flies (Hemerobiidae), are beneficial.
It is possibly for the purpose of feeding on parasitic mites that book-scorpions lodge themselves beneath the wing-cases of large tropical beetles; and the same explanation, in default of a better, may be extended to their well-known and oft-recorded habit of seizing hold of the legs of horse-flies or other two-winged insects.
The eggs and larvae of the fire-flies are luminous as well as the perfect beetles.
Flies, lice, gadflies and mosquitoes are the worst of the insect plagues.
Of the families Belo- stomatidae, Nepidae, Corixidae and Hydrometridae have a pulsating sac at each knee-joint to assist the flow of blood through the legs, while in dragon-flies and locusts (Acridazdae) there is a ventral pulsating dia phragm, which forms the roof of a sinus enclosing the nerve-cords.
Some of these glands may be modified for special purposes - as silk-producing glands in caterpillars or as poisonglands in blood-sucking flies and bugs.
In moths and certain saw-flies there is no rupture of the membranes; the Russian zoologists Tichomirov and Kovalevsky have described the growth of both amnion and embryonic ectoderm around the yolk, the embryo being thus completely enclosed until hatching time by both amnion and serosa.
These later stages, comprising the greater part of the larval history, are adapted for an inquiline or a parasitic life, where shelter is assured and food abundant, while the short-lived, active condition enables the newly-hatched insect to make its way to the spot favourable for its future development, clinging, for example, in the case of an oil-beetle's larva, to the hairs of a bee as she flies towards her nest.
The may-flies, however, offer a remarkable exception to this rule.
Includes the single family of Panorpidae (scorpion-flies), often comprised among the Neuroptera.
He obtains a magic glass cage, yoked with eight griffins, flies through the clouds, and, thanks to enchanters who know the language of birds, gets information as to their manners and customs, and ultimately receives their submission.
In life, however, its appearance must be wholly unlike, for it rarely flies, hops actively on the ground or among bushes, with its tail erect or turned towards its head, and continually utters various and strange notes, - some, says Darwin, are "like the cooing of doves, others like the bubbling of water, and many defy all similes."
Bees carry the spores of Scierotinia as they do the pollen of the bilberries, and flies convey the conidia of ergot from grain to grain.
The well-known "fire-flies" of the tropics are large click-beetles (Elateridae), that emit light from paired spots on the prothorax and from the base of the ventral abdominal region.
Flies and frogs were also complained of, and Sidonius, writing in the 5th century, complains bitterly of the "feculent gruel" (cloacalis puts) which filled the canals of the city, and gave forth fetid odours when stirred by the poles of the bargemen.
The relation of the Diptera (two-winged flies, or flies proper) to the other Orders is dealt with underHexapoda.
The chief characteristic of the Diptera is expressed in the name of the Order, since, with the exception of certain aberrant and apterous forms, flies possess but a single pair of membranous wings, which are attached to the meso-thorax.
The antennae of Diptera, which are also extremely important in classification, are thread-like in the more primitive families, such as the Tipulidae (daddy-long-legs), where they consist of a considerable number of joints, all of which except the first two, and sometimes also the last two, are similar in shape; in the more specialized families, such as the Tabanidae (horse-flies), Syrphidae (hover-flies) or Muscidae (house-flies, blue-bottles and their allies), the number of antennal joints is greatly reduced by coalescence, so that the antennae appear to consist of only three joints.
As a rule flies are of small or moderate size, and many, such as certain blood-sucking midges of the genus Ceratopogon, are even minute; as extremes of size may be mentioned a common British midge, Ceratopogon varius, the female of which measures only 14 millimetre, and the gigantic Mydaidae of Central and South America as well as certain Australian robber-flies, which have a body 1-11n.
Flies seem capable of adapting themselves to extremes of cold equally as well as to those of heat, and species belonging to the order are almost invariably included in the collections brought back by members of Arctic expeditions.
That Diptera of the type of the common house-fly are often in large measure responsible for the spread of such diseases as cholera and enteric fever is undeniable, and as regards blood-sucking forms, in addition to those to which reference has already been made, it is sufficient to mention the vast army of pests constituted by the midges, sand-flies, horseflies, &c., from the attacks of which domestic animals suffer equally with man, in addition to being frequently infested with the larvae of the bot and warble flies (Gastrophilus, Oestrus and Hypoderma).
Lastly, as regards the phytophagous forms, there can be no doubt that the destruction of grass-lands by "leatherjackets" (the larvae of crane-flies, or daddy-long-legs, - Tipula oleracea and T.
The best-known dipterous pests are the Hessian fly (Cecidosnyia destructor), the pear midge (Diplosis pyrivora), the fruit flies (Tephritis Tyroni of Queensland and Halterophora capitata or the Mediterranean fruit fly), the onion fly (Phorbia cepetorum), and numerous corn pests, such as the gout fly (Chloropstaeniopus) and the frit fly (Oscinis frit).
Hundreds of acres of wheat are lost annually in America by the ravages of the Hessian fly; the fruit flies of Australia and South Africa cause much loss to orange and citron growers, often making it necessary to cover the trees in muslin tents for protection.
5); it flies back to the prunes to lay its eggs when the hops are ripe.
2, II), while in moths and caddis-flies they are reduced to mere vestiges or altogether suppressed.
In many bloodsucking flies, for example, the galea is absent, while the lacinia becomes a strong knife-like piercer and the palp is well developed.
Those of the dragon-flies (Odonata) have been described in detail by R.
13, od) leads, and in some of the more primitive insects (bristle-tails, earwigs, may-flies) the two oviducts open separately direct to the exterior.
In some midges and in caddis-flies the serosa becomes ruptured and absorbed, while the germ band, still clothed with the amnion, grows around the yolk.
Palmen (1884) on these ducts have shown that in may-flies and in female earwigs the paired mesodermal ducts open directly to the exterior, while in male earwigs there is a single mesodermal duct, due either to the coalescence of the two or to the suppression of one.
27) and some dragon-flies and midges.
Includes the single family of the Perlidae (Stone-flies), formerly grouped with the Neuroptera.
Comprises gall-flies, ichneumon-flies, ants, wasps, bees.
In certain gall-flies (Cynipidae) no males are known to exist at all, and the species seems to be preserved entirely by successive parthenogenetic generations.
And of the muscid flies, an anterior and a posterior endodermThe embryo thus becomes transferred to the dorsal face of the egg, rudiment both derived from the " endoblast " become apparent but at a later stage it undergoes reversion to its original ventral at an early stage, in close association with the stomodaeum and position.
Other flies act as diseasecarriers, including the mosquitoes (Anopheles), which not only carry malarial germs, but also form a secondary host for these parasites.
Beetles and larvae are frequently carnivorous in habit, hunting for small insects under stones, or pursuing the soft-skinned grubs of beetles and flies that bore in woody stems or succulent roots.