194 



Croidurg of Natural fftt 



time it roves the field and forest, or disports 

 itself on the margin of the silvery stream 

 lightly traversing the air in a thousand 

 directions, and expanding its gossamer wings 

 to the sun how short is its aerial and ter- 

 restrial life, compared with that which it 

 passed in its aquatic state ! Scarcely have 

 the frosts of autumn nipped the tenderest 

 plant, ere the whole tribe of Libellulae perish 

 from the cold. 



Among the varieties of the Dragon-fly, 

 many of them may sometimes be observed 

 in the same field, or flying within a small 

 distance of each other on the borders of their 

 natal stream ; and though they differ in 

 their size and variegations, their general 

 form and habits correspond too nearly to be 

 mistaken for any other winged insects. A 

 specific notice of each may therefore be 

 thought unnecessary. We shall, however, 

 avail ourselves of Dr. Shaw's description of 

 one species of " exotic " Libellula, and his 

 concluding remarks relative to the extraor- 

 dinary character of the eyes of these insects 

 in general. "The Libellula Lucretia is a 

 native of the Cape of Good Hope (or rather 

 of S. America), and is distinguished by the 

 excessive length of its slender body, which 

 measures not less than five inches and a half 

 in length, though scarcely exceeding the 

 tenth of an inch in diameter : the wings are 

 transparent, of a slender or narrow shape, 

 as in the L. pudla, to which this species is 

 allied in form, and measures five inches and 

 a half in extent from tip to tip : the colour 

 of the head and thorax is brown, with a 

 yellowish stripe on each side, and the body 

 is of a deep mazarine blue. 



" I should not dismiss the genus Libellula 

 without observing that in some species, and 

 particularly in the L. varia, grandis, &c., 

 the wonderful structure of the cornea or ex- 

 ternal coat of the eye, which prevails in by 

 far the major part of the insect tribe, is ex- 

 hibited with peculiar distinctness. Even a 

 common magnifier, of about an inch focus, 

 demonstrates that the cornea is marked by 

 a prodigious number of minute decussating 

 lines, giving a kind of granular appearance 

 to the whole convexity : but when micro- 

 scopically examined, it exhibits a continued 

 surface of convex hexagons, and if cut from 

 the head, and cleared from its internal pig- 

 ment, it appears perfectly transparent, and 

 seems to consist of an infinity of hexagonal 

 lenses of equal convexity on both surfaces. 

 This is a subject on which much might be 

 said ; but the compass of the present pub- 

 lication forbids too circumstantial a descrip- 

 tion of minute and disputable particulars. 

 It may be sufficient to observe that on each 

 eye of this animal, according to the compu- 

 tation of Lewenhoek, there are about 12,544 

 of these lenses." 



To those who would study in detail the 

 members of this group, we would recommend 

 the volume of Rambur in the "Suites a 

 Buffon," and the works of Van der Linden, 

 De Selys Longchamps, and especially Char- 

 pentier. In this country, J. C. Dale, Esq. 

 F.L.S., has made the group a special subject 

 of study, and Mr. W. Evans has published 

 rough figures of all the British species, which 



may prove useful in identifying them. Dra- 

 gon-flies are often found in a fossil state, as 

 early as in the lias formation. [See PJETA- 

 LUKA.] 

 DRILL. [See APE.] 



DRIVER ANT. The local name given to 

 a species of Hymenopterous insect belonging 

 to the family of Ants. Its name is Anomma 

 arcens. The following very interesting ac- 

 count is derived from a paper by the Rev. 

 Dr. Savage, an American missionary on the 

 coast of West Africa, and published in the 



Transactions of the Entomological Society' ' 

 for 1847. 



The writer prefaces his narrative by saying 

 that he is not aware that the insect in ques- 

 tion has ever been described, or that it exists 

 in any of the European cabinets ; but he 

 thinks it is, without doubt, that of which 

 Mr. Smeathman speaks, when he says, " one 

 species, which seems at times to have no 

 fixed habitation, ranges about in vast armies. 

 By being furnished with very strong jaws, 

 they can attack any animal whatever that 

 impedes their progress, and there is no escape 

 but by immediate flight or instant retreat to 

 the water. The inhabitants of the negro 

 villages are frequently obliged to abandon 

 their dwellings, taking with them their 

 children, &c., and wait till the ants have 

 passed." Dr. Savage says it is evidently 

 closely allied to the Attu cephalotes of Fabri- 

 cius, found in the West Indies and South 

 America, and like that named by the French 

 " Fourmide visite," would be not inappropri- 

 ately styled the " visiting ant," though he 

 considers the appellation Driver more signi- 

 ficant of its habits. " Its domicile," he says, 

 " if such it may be called, consists of a 

 shallow excavation under the roots of trees, 

 shelving rocks, and almost any other sub- 

 stance that will afford a shelter ; not origi- 

 nating with themselves, but adopted and 

 completed as the wants of their community 

 may require ; their mode of life not admit- 

 ting of cells and magazines, and other in- 

 terior arrangements, by which the domiciles 

 of other ants more retiring and less aggres- 

 sive in their habits are characterized. 



" Their sallies are made in cloudy days, 

 and in the night, chiefly in the latter. This 

 is owing to the uncongenial influence of the 

 sun, an exposure to the direct rays of which, 

 especially when the power is increased by 

 reflection, is almost immediately fatal. If 

 they should be detained abroad till late in 

 the morning of a sunny day by the quantity 

 of their prey, they will construct arches 

 over their path, of dirt agglutinated by a 

 fluid excreted from their mouth. If their 

 way should run under thick grass, sticks, 

 &c., affording sufficient shelter, the arch 

 is dispensed with ; if not, so much dirt is 

 added as is necessary to eke out the arch in 

 connection with. them. In the rainy season, 

 or in a succession of cloudy days, this arch 

 is seldom visible ; their path, however, is 

 very distinct, presenting a beaten appear- 

 ance, and freedom from every tiling movable. 

 They are evidently economists in time and 

 labour ; for if a crevice, fissure in the ground, 

 passage under stones, &c., come in their 



