APT

apt, a town of south-eastern france, in the department of vaucluse, on the left bank of the coulon, 41 m. e. of avignon by rail. pop. (1906) 4990. the town was formerly surrounded by massive ancient walls, but these have now been for the most part replaced by boulevards; many of its streets are narrow and irregular. the chief object of interest is the church of sainte-anne (once the cathedral), the building of which was begun about the year 1056 on the site of a much older edifice, but not completed until the latter half of the 17th century. many roman remains have been found in and near the town. a fine bridge, the pont julien, spanning the coulon below the town, dates from the 2nd or 3rd century. a tribunal of first instance and a communal college are the chief public institutions. the chief manufactures are silk, confectionery and earthenware; and there is besides a considerable trade in fruit, grain and cattle. apt was at one time the chief town of the vulgientes, a gallic tribe; it was destroyed by the romans about 125 b.c. and restored by julius caesar, who conferred upon it the title _apta julia_; it was much injured by the lombards and the saracens, but its fortifications were rebuilt by the counts of provence. the bishopric, founded in the 3rd century, was suppressed in 1790. aptera (greek for "wingless"), a term in zoological classification applied by linnaeus to various groups of wingless arthropods, including some of the insects, the centipedes, the millipedes, the arachnida (scorpions, spiders, &c.) and the crustacea. in modern zoology the term has become restricted to the lowest order of the class hexapoda or true insects. this order includes the bristle-tails and the springtails. [illustration: from _knowledge_ fig. 1.--a typical thysanuran (_machilus maritima_). female, ventral view. ii.-x., appendages on 2nd to 10th abdominal segments. the eversible sacs on the abdominal segments are shown, some protruded and some retracted. ovp, ovipositor. mn, mandible, and mxl, maxillula, dissected out of head.] many wingless insects--such as lice, fleas and certain earwigs and cockroaches--are placed in various orders together with winged insects to which they show evident relationships. in such cases the absence of wings must be regarded as secondary--due to a parasitic or other special manner of life. but the bristle-tails and springtails, which form the modern order aptera, are all without any trace of wings, and, on account of several remarkable archaic characters which they exhibit, there is reason for believing that they are primitively wingless--that they represent an early offshoot which sprang from the ancestral stock of the hexapoda before organs of flight had been acquired by the class. _characters._--in addition to the complete absence of wings and of metamorphosis, the aptera are characterized by peculiar elongate mandibles (figs. 1, mn.; 2, 4), with toothed apex and sub-apical grinding surface, like those of certain crustacea; by the presence between the mandibles and maxillae of a pair of appendages (superlinguae or maxillulae), fig. 1, mxl., which are absent or vestigial in all other insects; and, in most genera, by the presence in the adult of abdominal appendages used for locomotion, these latter varying in number from one to nine pairs. among peculiarities of the internal organs the segmental arrangement of the ovaries in most members of the order is noteworthy. many aptera are covered with flattened scales like those of moths. _classification._--the aptera are divided into two divergent sub-orders, the _thysanura_ (q.v.) or bristle-tails, and the _collembola_ or springtails. _thysanura._--the bristle-tails have an abdomen of eleven segments, the tenth usually carrying a pair of long many-jointed tail-feelers (cerci, fig. 1, x.); sometimes a median, jointed tail-appendage is also present. to these feelers the popular name is due. there may also be abdominal appendages--in the form of simple unjointed stylets (fig. 1, ii.-ix.), accompanied by paired eversible sacs, probably respiratory in function--on eight (or fewer) other abdominal segments. the head of a bristle-tail carries a pair of compound eyes and a pair of elongate many-jointed feelers. the air-tube system is developed in varying degree in different bristle-tails, the number of pairs of spiracles being three (_campodea_), nine (_machilis_), ten (_lepisma_), or eleven (_japyx_). four families of thysanura are usually recognized. in the _machilidae_ and _lepismidae_ (these two families are known as the ectotrophi) the maxillae are like those of typical biting insects, and there is a median tail-bristle in addition to the paired cerci; while in the _campodeidae_ and _japygidae_ (which form the group entotrophi) the jaws are apparently sunk in the head, through a deep inpushing at the mouth, and there is no median tail-bristle. the cerci in _japyx_ are not, as usual, jointed feelers, but strong, curved appendages forming a forceps as in earwigs. [illustration: from carpenter, _proc. r. dub. soc._, vol. xi. fig. 2.--structure of collembola. 1. _isotoma hibernica_. side view. 2. " ocelli and post-antennal organ of right side. 3. " tip of terminal antennal segment with antennal organ. 4. " mandible. 5. " tip of left dens with mucro. outer view. 6. " hind-foot with claws. x 240. 7. _entomobrya anomala_. catch.] _collembola._--in springtails, or _collembola_, the jaws are sunk into the head, as in the entotrophous thysanura; the head carries a pair of feelers with not more than six (usually four) segments, and there are eight (or fewer) distinct simple eyes on each side of the head (fig. 2, 1, 2). these are in some genera like the single elements (_ommatidia_) of a compound insect eye, in others like simple ocelli. the abdomen consists of six segments only. the first of these usually carries a ventral tube, furnished with paired eversible sacs which assist the insects in walking on smooth surfaces, and perhaps serve also as organs for breathing. from the researches of v. willem it appears that the viscid fluid which causes the adherence of the ventral tube is secreted by a pair of glands in the head whose ducts open into a superficial groove leading from the second maxillae backward to the tube on the first abdominal segment. the third abdominal segment usually carries a pair of short appendages whose basal segments are fused together; this is the "catch" (fig. 2, 7), whose function is to hold in place the "spring," which is formed by the fourth pair of abdominal appendages--also with fused basal segments. in most collembola the spring appears to belong to the fifth abdominal somite, but willem, by study of the muscles, has shown that it really belongs to the fourth. the fused basal segments of the appendages form the "manubrium" of the spring, which carries the two "dentes" (usually elongate and flexible), each with a "mucro" at its tip (fig. 2, 5). the fifth abdominal segment is the genital, and the sixth the anal somite. the spring serves the collembola which possess it as an efficient leaping-organ (see springtail). but in some genera it is greatly reduced and in many quite vestigial. most springtails are without air-tubes, and breathe through the general cuticle of the body. but in one family (_sminthuridae_) a spiracle, opening on either side between the head and the prothorax, leads to a branching system of air-tubes. the _sminthuridae_ are further characterized by the globular abdomen, which shows but little external trace of segmentation, and by the well-developed spring. in the _entomobryidae_ the body is elongate and clearly segmented, but the dorsal region (tergum) of the prothorax is much reduced and the head downwardly directed; the spring is well developed. in the _achorutidae_ the head is forwardly directed, the tergum of the prothorax conspicuous, and the spring small or vestigial. in many genera of springtails a curious post-antennal organ, consisting of sensory structures (often complex in form) surrounded by a firm ring, is to be noticed on the cuticle of the head between the eyes and the feelers. it may be of use as an organ of smell. other sensory organs occur on the third and fourth antennal segments in the _achorutidae_ and _entomobryidae_ (fig. 2, 3). _distribution and habits._--the aptera are probably the most widely distributed of all insects. among the bristle-tails we find the genus _machilis_, represented in europe (including the faeroe islands) and in chile; while _campodea_ lives high on the mountains and in the deepest caves. the springtails have even a wider distribution. the genus _isotoma_, for example, has some of its numerous species in regions so remote as alaska, franz josef land, the sandwich islands, the south orkneys, graham land, kerguelen and south victoria land. as it is unlikely that these delicate insects could be transported across sea-channels, their wide and discontinuous range suggests both their great antiquity and the former existence of continental tracts over which they may have travelled to their present stations. springtails and bristle-tails live in damp concealed places--under stones or tree-bark, in moss, and in the decaying vegetable or animal matter which serves as food for most of them. some species, however, eat fresh plant-tissues. a species of bristle-tail (_machilis maritima_) and quite a number of springtails haunt the sea-coast at or below high-water mark. in such localities many thousands of individuals may sometimes be found associated together. the insect fauna of limestone caves both in europe and north america is largely composed of aptera, especially collembola. _geological history._--a supposed thysanuran from the silurian of new brunswick has been described by g.f. matthew, and another genus from the french carboniferous by c. brongniart. not till the tertiary do we find remains of aptera in any quantity, species both of living and extinct genera being represented in the amber. _development._--the embryonic development of several genera of aptera, which has been carefully studied, will be more suitably described in comparison with that of other insects than here (see hexapoda). bibliography.--the modern study of the aptera may be said to date from the classical memoirs of t. tullberg, "sveriges podurider," in _kongl. svensk vetensk. akad. handl._ x., 1872, and sir j. lubbock (lord avebury), "monograph of the collembola and thysanura," _ray society_, 1873. in these, full references to the older literature will be found. subsequently our knowledge of the thysanura has been markedly advanced by j.t. oudemans, _bijdrage tot de kennis den thysanura en collembola_ (amsterdam, 1888); b. grassi, who published between 1885 and 1889 a series of memoirs entitled "i progenitori dei miriapodi e degli insetti," in the _atti accad. di scienz. nat. catania_, and the _memor. r. accad. dei lincei_; and v. willem, whose "recherches sur les collemboles et les thysanoures," in _mem. cour. acad. roy. belgique_, lviii., 1900, are indispensable to the student. in addition to this work of willem, valuable anatomical papers on collembola have been published by h.j. hansen (_zool. anz._ xvi., 1893), j.w. folsom (_bull. mus. comp. anat. harv._ xxxv., 1899), c. borner (_zool. anz._ xxiii., 1900), and k. absolon (_zool. anz._ xxiii. and xxiv., 1900, 1901), the two latter writers having paid especial attention to the peculiar post-antennal and antennal sense-organs of springtails. absolon has also written on the collembola of caves. these writers, with h. schott, c. schaffer and others, have published many systematic papers on collembola, as has f. silvestri on thysanura. british species are mentioned in lubbock's monograph; for recent additions see g.h. carpenter and w. evans (_proc. r. phys. soc. edinb._ xiv., 1899, and xv., 1903). (g. h. c.) apteral (from the gr. [greek: apteros], wingless, [greek: a-], privative and [greek: pteros], a wing), an architectural term applied to amphiprostyle temples which have no columns on the sides; in the ionic temple on the acropolis at athens known as nike apteros, the adjective is used, not as applying to the goddess of victory but to the absence of any peristyle on the sides. aptian (fr. _aptien_, from apt in vaucluse, france), in geology, the term introduced in 1843 by a. d'orbigny (_pal. france cret._ ii.) for the upper stage of the lower cretaceous rocks. in england it comprises the lower greensand and part of the speeton beds; in france it is divided into two sub-stages, the lower, "bedoulian," of bedoule in provence, with _hoplites deshayesei_ and _ancyloceras matheroni_; and an upper, "gargasian," from gargas near apt, with _hoplites furcatus_ (_dufrenoyi_) and _phylloceras guettardi_. to this stage belong the _toucasia_ limestone and _orbitolina_ marls of spain; the _schrattenkalk_ (part) of the alpine and carpathian regions; and the _terebrirostra_ limestone of the same area. parts of the flysch of the eastern alps, the biancone of lombardy, and _argile scagliose_ of emilia, are of aptian age; so also are the "trinity beds" of north america. deposits of bauxite occur in the aptian hippurite limestone at les baux near aries, and in the pyrenees. the aptian rocks are generally clays, marls and green glauconitic sands with occasional limestones. (see greensand and cretaceous.)