tit 



APHRITE. 



APTKliYX. 



loit generation, wliicli, acoonling to the species of Aphis, i* the 

 li. niiitli. r eleventh, the power which they possess of producing 

 iiiiliviituiUii like themselves ceases. In the last generation winga are 

 acquired, and male insect* also with winga appear. It a these inaecte 

 which produce eggs, and deposit thnm where, under the genial inllu. n.-.-< 

 of the nun, they are hatched, and thus produce the multitudes which 

 make the attacks of these creature* so remarkable. 



The number of species of Aphis is very large. In the ' I 

 Specimens of Homopterous Insects' in the collection of the British 

 Museum, drawn Up by Hr. Francis Walker, 326 species of this genus 

 are described. Almost every species of plant gives support to n 

 different species of Aphis, each of which haa been described with very 

 great accuracy in the list above mentioned. 



The effects of the attacks of these insects is sometimes of national 

 importance. In the year 1802 the hop-duty fell from 100.000/, to 

 14,0001,, on account of the great increase of the Ap'ei-. When the 

 Aphis has been absent the duty has risen as high as 500,000/. 

 The Apkit Rotas is most destructive to the beautiful plant on win. h 

 it is constantly found. Apple-trees and pear-trees ore attacked with a 

 species which injures greatly their produce. In most cases these 

 insects are green, but a block species attacks the bean ; whole acres 

 of these plants will be suddenly covered by these insects. Their 

 attacks on all plants seem regulated by the health of the plant If 

 atmospheric conditions occur which render plants unhealthy, then tin- 

 Aphis makes its appearance. If these cease, the Aphis then disappears 

 also, and one crop of plants will be attacked several times in the 

 same year. The Aphides have their natural enemies. The larvae of 

 the Lady-Bird (Coccintlla), the Syrphui or Bee-like Fly, the Hemerobin 

 prria, and several species of Ichneiunonida, devour with great avidity 

 several species of Aphis. 



The chief remedy for the destruction of the Aphis is tobacco. 

 Where plants can be brought together under cover they may be easily 

 exposed to tobacco fumes, but in the open air this is not so easily 

 effected. In this case the best plan is to apply the tobacco in 

 water. The affected branches or parts of plants may be syringed 

 with the infusion, anil afterwards washed with pure water. 



AI'HHITE, in Mineralogy, a crystalline variety of carbonate of 

 lime. 



APHRODITA, a genus of Dorsibranchiate Annclides. It is easily 

 known from the rest of the order by two longitudinal ranges of 

 broad membranous scales covering the back, and under which the 

 gills lie concealed in form of little fleshy crests. The body is 

 generally flattened, and shorter and broader than ill other Aimelides. 

 [ANNELIDA.] 



APIOCRINI'TES (Miller), a Fossil genus of Criuoidea, found in the 

 Oolitic formations and in the Chalk. 



A'PIUM, a genus of plants belonging to the order UmbeUiferir. 

 The only species of this genus of any importance is the Common 

 Celery (Apium graveoleni). This valuable vegetable is found naturally 

 in the ditches of almost every port of Europe. It is even mot with in 

 the Falkland Islands, where, if it was originally carried thither, 

 it has naturalised itself. In this country it is very common in many 

 places, as for instance in the ditches near Sandwich. 



It is a remarkable fact that this plant, which is so sweet and 

 wholesome when cultivated, is altogether acrid and unfit for food 

 when wild. It is by some supposed that the difference between the 

 quality of the two states is owing to so large a part of the stem and 

 leaves of the cultivated species being hidden from the action of light 

 by the >il which is heaped up about it, and being in consequence 

 unable to generate in much abundance the peculiar principle on which 

 the acridity depends. Whatever may be the value of this explanation. 

 it evidently does not apply to the variety called Celeriac, in which the 

 sweetness and wholesome character of cultivated celery are m iii 

 although the leaves ore not at all deprived of the full influence of 

 light. [CELERY, in ARTS AXD Sc. Div.J 



APOCYNA'CEiK, 1 ) igbaiien, a natural order of plants belonging 

 to the Monopetolous subdivision of the Exogenous class. Among these 

 they are known by their flowers being perfectly symmetrical, the 

 segments of the corolla all twisted one way, like a ('at.h.-nii'- w'e I. 

 five distinct stamens, a superior ovarimn which when ripening 

 divides into two ports that diverge from each other at right 

 and by their stems yielding, when wounded, a copious milk. The 

 milk is generally poisonous, and that quality is general in tl< 

 which abounds in plants the action of whose juices upon the human 

 body is more or less violent. Among these, the Tanghiu poison of 

 Madagascar [TANGII i xi. \1 and .Vur romica [STRYCIINOS] ore remarkable 

 instances. But some of the species are not unwholesome ; us the 

 II i llya, or Milk-Tree of Dcmerura, and the Cream-Fruit of 

 Leone. Caoutchouc is yielded in abundance by Va/ica gun,, 

 l/rceola eUutica, and Wittugkby eduJ.ii. Several other species yield 

 medicinal agents, but they are not much employed in the European 

 practice of medicine. Considering, however, the great prevalence of 

 poisonous qualities in the order, drugs obtained from any of its 

 species should be administered with very great caution, until it bos 

 been ascertained that they may be employed without danger. The 

 order Apocynacea is only distinguishable from Aidcpiatiacctt by the 

 stamens being distinct from the pistil, and by the pollen not being 

 contained in little waxy bags. 



A'PODKS, in Zoology, on order of Ki.-dics, including, according to 

 nniran system, all those which want, the ventral linn. hut 

 restricted by Baron Cuyi.-r to those which. K, >ides possessing this 

 character, are likewise Malacopterygious. In the latter mil- 

 Apodal Fishes compose a small natural family, almost restrii (<-.! to ih 

 great genus Murtrna, and of which the Common Kel offers a good 

 and familiar example. 



APOPHYLLITE, a crystallised mineral. whose fundamental form 

 is the square prism, fig. 1. Its most general iuiidihY.it i-u i - . ' 

 by supposing the angles of fig. 1 cut off, sn as to give rise to a plane 

 triangular surface, as is seen at in tig. _' ; these face* it, from the 

 plane cutting deeper into the original crystal till they intersect each 

 other, frequently lose their triangular form, and of cour-e, at the 

 same time, the face P again becomes a square, and the prism will be 

 terminated by the form seen in tig. :!. I )n account of thc.-e modifications, 

 Apophyllite sometimes assumes the form in fig. 4. 



Pig. 1. 





ip. 3. 





The inclination of P on a is 120 5' 

 L on a is 128 20' 



a on a is 104 18' 



The structure of this mineral is lamellar, and admits of cleavage in 

 directions parallel to the sides of the regular prism, but most readily 

 in the perpendicular to it axis. Its colour is white or gray, some- 

 times tinged green or red. It possesses various degrees of transparency, 

 and occurs even opaque. In hardness it approaches nearly t o A ] 

 and its density varies from 2'3 to 2'5. Before the blow-pipe it forms 

 a white glass. Its chemical constitution is stated as follows : 



8 (Co -H 3 ti) + (K + 6 Si) + 16 Aq 

 and the mineral is therefore an hydrated silicate of potash and 1 



Apophyllite has been found in the mines of magnetic iron-ore of 

 Sweden and Norway ; in the lead-mines of the Hare Mountains ; also 

 in the cavities of several basaltic rocks, at Marienberg in Bohemia ; 

 at Fossa in the Tyrol ; in the Isle of Skye, &c. In the basalts it is 

 usually accompanied by Analciux and Stilbite. 



This mineral is sometimes called / Mliln is a white variety. 



APOTHE'CIA (from the Greek ivo0riKi), a case, a repository t, in 

 Botany, a name given to some of the organs of reproduction in I Vy/./'i 

 t/amia. In Lichens the reproductive matter appears on the surface of its 

 frond or thallus in two forms. First, in the form of little coloured cups 

 or lines with a hard disk surrounded by a rim, and containing tubes 

 filled with Kporules ; and secondly, in the form of little heaps of 

 pulverulent matter, which are scattered m.-r the surface of the 

 thallus. These last are colled Soredia ; tho fir.-t. A/x,H,, 

 organs form the principal means of distinguishing the various forms 

 of lichens, and consequently it lion been found convenient, to indicate 

 mi nor points in tip ir.-t nicture by other names. Thus tin- Apoth.-.-ium, 

 which in Knglish i.s called a Shield, lias various names occ, 

 form : Scu'ellum is a shield with an elevated rim ; 1'ilin, a flat shield ; 

 Tuberculum, a convex shield ; Trica or Gyroma, a furrowed shield ; 



. a linearshicld ; Globutiu,i\ round deciduous .diield : /V 

 an orbicular hemispherical shield. The parts of the Apoth.'eium or 

 Shield have also stinct name- : th is the 



inside of the shield, in which the sporulcs are immersed ; Ifii/iu'' 

 is the' substance that surrounds or overlies the perithccium : A 

 is the disk of the shield, which contains the sporules and their oases; 

 and .l-i are the tubes in which the sarnies are contained. 



/'fcia is also the name given to the coses in which tin 

 of reproduction..)' many of the Alyre are contained. The- r.-|.n>.i 

 granules contained in the Apothecia of both Lichens and Ah 



called by some writers tinin/illl. 



.\rSKNHi: SI \ , \ ...m.), a genus of Fossil Polypiaria, from Uu 

 great Oolite near Bath. 



A1TKKYV ofStnithii.n. I'.ii. 1-. inh.o.iiin _ Australia and 



the islands of Y.-w X"al.md. It v. v I >r. Shaw, who 



regarded it as on extinct form of bird. It evidently belongs to a 

 group of birds that were destined to live 0:1 the earth, only as long as 

 they were free from the attacks of carnivorous enemies endowed \vith 

 greater powers of motion than *' 



birds, not belonging to the Struthious is the Uod 



Solitaire, seem already to have become extinct; whilst the smaller 



