27.2 



DEODARA-DESMODIUM. 



rooted herbs, chiefly natives of Europe. Linnueau 

 class Tclradynamia, and natural order Cruclferte. 

 These plants are nearly allied to Cardamine, but differ 

 in having tooth-like scales at the root. They grow 

 readily in light soil, and are increased by dividing 

 the roots. 



DEODAR A. The specific name of a cedar found 

 in India by Dr. Roxburgh, and introduced into this 

 country in 1822. 



DERMESTID^E, a family of coleopterous insects 

 belonging to the section Pentamera, and sub-section 

 Nccrophaga. This family is of small extent, but com- 

 prises several very obnoxious species of beetles. The 

 body is generally oval, rounded at each end and some- 

 what convex, the antennae short and clavatc, sometimes 

 varying in the sexes ; the legs short, with the tarsi 

 five-jointed, and not contractile as in the Byrrhidce, 

 the tibia being long and narrow. The genera are 

 Dermestes, Ctesias, Mcgatoma, Attagenns, Limnichus, 

 Trogoderma, Globicornis, and Anthrenus. The last 

 named genus, as well as Aspidiphorm and Throscus, 

 seem to unite this family with the liyrrliidae or pill- 

 beetles, with which they are associated by some 

 authors. Of these genera the only one which offers 

 any interesting observations in respect to their econo- 

 my, is the first, which is the type of the family, and 

 which has received its name from the circumstance 

 that the species of which it is comprised especially 

 attack dried skins, the Greek word derma signifying 

 a skin. The mischief which they thus often occasion 

 to very costly materials, has occasioned them to be 

 well-known. The perfect insect, on the contrary, 

 seems only to live for the purpose of continuing its 

 kind, being often found upon flowers, and if it fre- 

 quents animal matter, it is only in order there to 

 deposit its eggs instead of producing fresh ravages. 



It is chiefly in collections of natural history, and in 

 the warehouse of the furrier, that these injuries are 

 committed ; in the former they entirely destroy pre- 

 pared beasts, birds, and insects, and in the latter all 

 kinds of skins, of which they gnaw the surface so as 

 to cause the hair entirely to fall off. They also attack 

 the carcases of animals exposed in the fields, devour- 

 ing all the fleshy and tendinous parts, so as to make 

 perfect skeletons of their prey. They also feed 

 upon bacon (whence the name of the typical species 

 Dermestes lardarius), feathers, horns, &c. Indeed, it 

 is difficult to guard against their attacks : they elude 

 our search by their small size, and our precautions 

 by their perseverance. Nevertheless, in the great 

 economy of nature, it cannot be denied that these 

 animals tend towards the general good by destroying 

 those kind of putrifving matters, and converting them 

 into a material serviceable for the support of plants, 

 inasmuch as that the air and moisture do not come 

 into action towards the same end so quickly. With 

 the assistance, therefore, of the Silphce, Histercs, We- 

 crophagi, &c., these insects effect the i eduction to their 

 former elements of such portions of carcases as the 

 flesh-fly has spared, which attacks only the flesh when 

 in a fresh and moist state, and leaves the skin entire. 



The Dermestidce seem to prefer dark situations, where 

 they remain inactive, and move only when disturbed, 

 with a trembling kind of gait ; they are seldom seen 

 on the surfaces of the substances upon which they 

 feed, but conceal themselves. The larvae are long, 

 diminishing towards the tail, and terminating in a trun- 

 cated cone, having, also, two scaly horns on the last 

 segment of the body ; they are covered with long 



hairs, and have a scaly head armed with powerful 

 toothed jaws. They change their skin several times, 

 according to Gcedart amounting to ten : the extivia? 

 retain their form so as easily to be mistaken for the 

 larva? themselves ; the back of the head, and several 

 of the front segments exhibiting only a longitudinal 

 slit. The larvae, when full-grown, seek a convenient 

 retreat, preferring the remnants of the matters upon 

 which they have been feeding. The pupa is white, 

 with the eyes, and several transverse markings of a 

 brownish colour. When touched, it moves the abdo- 

 men with considerable force; the perfect insect, ap- 

 pears in about a month. The larva of Dermcstcxjief/i't 

 has a tail nearly as long as the body, composed of long 

 red hairs. The best remedy against the attacks of 

 these insects is the employment of arsenic in the pre- 

 paration of zoological specimens. 



The genus Dermestes is distinguished by having the 

 antennae eleven-jointed, shorter than the thorax, alike 

 in both sexes, with the last joint of the papillary palpi 

 shorter than the maxillae. There are four or five 

 British species, including the bacon-beetle D. lardnrius 

 which is of a black colour, with the base of the elytra 

 dirty ashen colour, having three small black spots. It 

 is about a quarter of inch long, and is very common 

 in houses, &c. D. murinus is generally found in moles, 

 hawks, and other carrion hung up in fields or against, 

 walh. D. vulpinus infests the hides imported by ship- 

 loads direct from the Brazils, and so great is tho 

 damage which it occasions, that we are informed that 

 the sum of ten thousand pounds has been offered as a 

 reward for its destruction. 



DESMANTHUS (Willdenow). A genus of 

 aquatic herbs and shrubs found in the East and West 

 Indies. Linna-an class and order Poll/gamut Monaecia, 

 and natural order Leguminosts, Generic character : 

 calyx five-toothed ; corolla with five distinct or united 

 spatulate petals; inferior flowers apetalous ; stamens 

 ten, rarely five ; pod evenly lengthened, and full of 

 seeds. This genus was formerly ranked among the 

 Mimosas, but separated by Willdenow. The terrestrial 

 species thrive in loam and moor earth, and are propa- 

 gated by cuttings ; the others are grown in water. 



DESMODIUM(Decandolle). An extensive genus 

 of herbaceous and shrubby plants, natives of America 

 and Asia. They belong to Diade/phia Dccandria, 

 and to the natural order Leguniinosce. Generic cha- 

 racter : calyx bracteate, somewhat two-lipped, the 

 upper one cleft, the lower one in three parts ; vexil- 

 him roundish ; keel obtuse; wings short; lomentum 

 jointed, with intervening compressions. Tm^e plants 

 are raised from seeds or cuttings, and are kept in 

 stove collections. Among them we find the moving 

 plant of Bengsl, formerly called Hrdysannn gyrnns, 

 but now Desmodium gyrans. This plant is an annual 

 or at most a biennial, having pinnate leaves, that is, 

 one pair of small opposite leaflets, with an odd one 

 of much larger size. These leaflets have a sponta- 

 neous motion when the plant is in a high temperature, 

 say between seventy-five and eighty degrees of Fah- 

 renheit,, and at the same time in bright sunshine. 

 The one slowly rises, while the other is depressed, 

 thus alternating in position for hours together. These 

 motions are only noticed when the plant is in the 

 highest vigour, not being observable in very young 

 or in very old plants. It is a phenomenon not yet 

 satisfactorily accounted for by phytologists, but it 

 has all the appearance in its action of that of a 

 hydraulic machine. 



