AGROSTIS A I. 



of the male armed with a forceps-like appendage. 

 The 



Lcs. autnmnnlcs (Leach) inhabit marshes, where 

 they may be found in August and September. 



In the genus CALEPTERYX, the wings are mem- 

 branous, without a real stigma, in place of which we 

 sometimes find transparent spots ; the abdomen of 

 the male is furnished with a forceps-like appendage. 





The Dragon-fly. 



The species vary much in the colour of the wings, 

 which arc sometimes bluish, brownish, black, pel- 

 lucid with a broad black fascia, pellucid with white 

 tips, or with brown tips and a white dot. 



Inhabits in the larva-state streams and rivers, and 

 in June and July may be found on the banks ; it is 

 abundant on the Lea, in the Hackney marshes. Tin's 

 is one of the species that require no preparation in 

 the preservation of their colours ; it is undoubtedly 

 one of the most brilliant British Agrionidcc. 



AGROSTtS. A name derived from the Greek 

 word aiypos, afield, and applied to a genus of grasses, 

 containing a considerable number of species, five of 

 which are natives of Great Britain. Generic charac- 

 ters . panicle or cluster of flowers loose ; calyx 

 consisting of two unequal scales or glumes longer 

 than the corolla ; corolla of two unequal valves, the 

 outer one frequently being furnished with an awn. 



AOROSTIS CAPILLARIS. a, the bivalvular one-flowered glume ; 

 b, the same opened, showing the flower ; c, the flower taken 

 out, to show the two valves of the calyx, arid the two scales ; 

 d, the seed. 



The Agrostis vulgaris, common bent-grass with 



its dwarf variety, and the Agrostis cmuna, or 

 brown bent-grass, are abundantly met with in fields 

 and pasture lands, and on account of thjeir earli- 

 ness are esteemed in agriculture. The Agrostis 

 setacea, or bristled-leaved bent-grass, is chit-fly found 

 in the south of England ; and the Agrostis spica 

 vcnti, or silky bent-grass, grows principally in the 

 neighbourhood of London. Another British species, 

 the Agrostis alba or stolonifera marsh bent-grass, is 

 very abundant in Ireland ; and under the name of 

 Fiorin-grass has been greatly praised by Irish 

 agriculturists for the puq>oses of fodder. It thrives 

 well in wet marshy soils, and is said to yield an abun- 

 dant and luxuriant crop. 



The Agrostis family arc met with in greatest 

 abundance in temperate regions. One species, the 

 Agrostis algida;, is interesting on account of being 

 one of the few plants found in Spitzbcrgen. In the 

 torrid zone the species of Agrostidca? have been 

 estimated to amount to fifty-eight, or one-fourteenth 

 of the whole grasses of that zone, while in the 

 temperate zone they amount to 220 or one-fifth of 

 the whole. In South America the Agrostidea? occur 

 most abundantly in the elevated mountainous districts. 



AI (The three-toed sloth, Achcus tridadi/Iii*.} 

 A genus of mammalia, belonging to the order of 

 cdentata, or toothless animals, and the natural family 

 of tardigrada or " SLOTHS," one of the most singular 

 in their forms and habits, and, according to our 

 notions, one of the most uncouth, in the whole range 

 of the animal kingdom ; but still as admirably adapted 

 to their haunts and modes of life as those species 

 whose forms we admire the most. 



The general characters of the group will be men- 

 tioned under its title ; but it may not be improper to 

 remark here, that the words "tardigrada" and "sloth," 

 the one expressive of sluggish motion, and the other 

 of indolent disposition, are both misapplied in the 

 case of these animals. In their own proper place, 

 they are neither laggard nor lazy ; and their forma- 

 tion, though, according to our common notions, it is 

 singular and ungainly, is not only better adapted to 

 their peculiar haunts than the structure of any other 

 animals with which we are acquainted, but better 

 than any that we could have imagined, if the problem 

 had been proposed to us to find the structure of an 

 animal without wings, which should find its food, 

 and spend the whole of its life, among the tops of 

 lofty trees in close forests, and so maintain its footing 

 there, as that no ordinary tempest not the hurricane 

 in the utmost of its fury could shake it to the earth. 



The haunts of these animals are the deep, extensive, 

 and luxuriant forests of South America ; forests in 

 which the trees are of giant growth, always green, so 

 close that rarely a beam even of the vertical sun 

 reaches the earth ; and they extend over districts so 

 wide, and are so festooned and interlaced with various 

 species of epidendra, or twining plants, that winds, 

 which would level our single trees with the ground, 

 or rend our most serried woods to tatters, barely 

 agitate their tops, or disfigure a few on the sides of 

 the openings. In all parts of nature there are coun- 

 teractions ; and in order that there may be seeds and 

 successions of races in those luxuriant forests, it is 

 necessary that there should be some consumers of the 

 superabundant foliage, which, otherwise, would com- 

 pletely exclude the sun and air, and the forest would 

 perish of the excess of its own exuberance, leaving 

 the naked and carpetless earth to be converted. In 



