42 



L E P A S L E P I D O P T E R A. 



the genus PentaLepus into the genera Pentalasmis and 

 Pollicipcdc, and in the genus Polylepas he separated 

 a species under the name of Scalpellum. Notwith- 

 standing the respect that is due to every thing Dr. 

 Leach has done towards facilitating the study of 

 natural history, we think in the present instance it is 

 much simplified by doing away with these extremely 

 minute distinctions, more important to the physiolo- 

 gist than instructive to the student. This family 

 Lepadicca, and the second JBalanidca, lead to the second 

 class, including the genus Chiton, and constituting 

 De Blainville's sub-type Malentozoaria or articulated 

 molluscs. The two iirst families constitute the class 

 Xcmalopoda, which answers to Cuvier and Lamarck's 

 Cirncpedrt ; this was divided by the latter into two 

 orders the first, Pedunculata, included all of those 

 molluscs whose bodies were supported on a fleshy 

 stem or tubular pedicle ; the second, Sessilia, or such 

 species as were permanently attached, or, to use an 

 expressive French term, soldered at their base, to the 

 place in which they were born, but little objeption 

 can be made to that arrangement; we, nevertheless, 

 give a preference to the simplicity of the classification 

 above described, and in every branch of the study of 

 nature we most earnestly recommend that the lead- 

 ing characters she constantly furnishes should guide 

 authors in forming the true basis of every system. 



LEP AS ( Linnaeus ; CIUREPEDA, Cuvier, Lamarck; 

 and NEMATOPODA, De Blainville). A class of mol- 

 luscs. See LEPADICEA. 



LEPIDIUM (Linnaeus). An extensive genus of 

 herbaceous plants, chiefly annuals, and for the most 

 part European weeds. They belong to Cruciferce 

 and are the pepperworts of English authors. The 

 species called L. sativa is the common garden cress, 

 and is a native of Persia ; another called L. olera- 

 ceum is the New Zealand cress, also now in cul- 

 tivation. 



LEPIDOPTERA (Linnaeus). A very extensive 

 and beautiful order of ibur-winged insects, known by 

 the English names butterflies and moths, and distin- 

 guished by having the wings composed of a double 

 transparent membrane, clothed on the upper and 

 under sides with minute coloured scales, resembling 

 dust or farina. The eyes are large and lateral, the 

 antenna; generally long and multi-articulate, and very 

 variable in form ; the mouth is composed apparently 

 of a long and spirally coiled organ, which, when 

 examined, is found to consist of two pieces, repre- 

 senting the maxillae, sometimes being provided with 

 a small jointed appendage or palpus at its base. This 

 very slender and delicate proboscis (or spiritrompe, 

 as it is called by Latreille, or antlia, by Kirby and 

 Spence), is employed by the insect in sipping the 

 sweets from the flowers, upon which alone it subsists, 

 and which, by its peculiar construction, is admirably 

 adapted for penetrating the narrowest blossoms. 

 When at rest it is rolled up in a coil, and defended 

 by two large and compressed palpi, composed of 

 thr.ee joints, inserted upon a lip fixed to the front of 

 the head. A more minute examination of the head, 

 however, proves that the rudiments of the other parts 

 of the mouth, namely, an upper lip and a pair of 

 mandibles, also exist, but in a very minute state, 

 and as it would seem, unfitted for any service in 

 feeding a peculiarity the more remarkable, because 

 in the preparatory state of the larva the mandibles 

 are very robust and horny, and constantly employed 

 in biting the leaves, which at that time serve for the 



support of the insect. The mesothorax is furnished 

 at the sides with a pair of large scales called pterv- 

 godes (Paraptera or tegulte, vide vol. ii., p. 858) 

 affixed at the base of the exterior wings on the upper 

 side. The abdomen is destitute of any sting, although 

 Dr. Burmeister has recently noticed an exotic species 

 contained in the Royal Collection at Berlin, which 

 appeared to be provided with an instrument of this 

 kind, but which we should be inclined rather to regard 

 as the acute extremity of the ovipositor, which, in 

 many of the species whose larvae are subterraneous 

 or subcortical in their habits, is long and acute. The 

 body of these insects is very pilose ; it is also very 

 variable in respect to its size ; those species which 

 are pre-eminently distinguished for their powers of 

 flight having the body, and especially the thorax, 

 very robust; whilst in the JKrycinidte, Gcomcti-ida; 

 and many others whose flight is weak, it is slender ; 

 indeed the last-mentioned family has, from this cir- 

 cumstance, obtained the name of slender bodies 

 amongst the English collectors. The form of the 

 pterygodes also is very variable, giving to the thorax 

 a diversity of appearance ; thus in the genus Cucullia 

 (moths belonging- to the family Noctuida:} the ptery- 

 godes are very large, and the thorax is pushed for- 

 wards, forming a sort of hood over the heads, whilst 

 in Xyliiia they are more elongated, so as to give the 

 sides of the thorax an elevated appearance, with the 

 centre depressed. The colour of the thorax is gene- 

 rallysimilar to that of the anteriorwings in the majority 

 of the moths, as well as in the butterflies, in which it 

 is clothed with fur hairs ; but the prothorax often 

 presents peculiarities of character : thus, in the larger 

 typical butterflies, PapUwnidcc, it is marked with two or 

 more red or yellow spots, sometimes uniting to form a 

 kind of collar. The wings are attached to the lateral 

 and superior part of the thorax, and are always pre- 

 sent; except in a few species of which the females are 

 apterous, or have the wings reduced to small and 

 useless appendages, the fine layers of membrane of 

 which the wings is composed, like the upper and lower 

 surface of a leaf, are kept expanded by a number of 

 longitudinal corneous veins or nerves, as they have 

 been called, but which Dr. Leach termed Pterygostia 

 or wing-bones. These nerves here, as in the Diptera 

 and Hymenoptera, according to their number and 

 position, offer very important characters, for generic 

 distribution, but which have been too much neglected 

 by authors. M. Boisduval, however, in his just pub- 

 lished Species General des Lepidopteres, Paris, 183G, 

 has performed good service in this branch of the science 

 by describing and delineating the nerves of the wings 

 of many of the species of lepidoptera'; although it is 

 proper to observe, in justice to our own countryman, 

 Jones, that he long ago published a valuable memoir 

 in the second volume of the Linnaean Transactions, 

 in which the same subject was well treated. The 

 structure of the scales, which give to the wings of 

 these insects all their beauty, has been described in 

 our article INSECT. The slight manner by which they 

 are attached to the wing causes them to scale off on 

 the least touch, so that by laying a butterfly in a 

 reversed position on a piece of gummed paper, an 

 exact impression of its markings will be obtained ; the 

 scales, however, being reversed, the broad extremity 

 of each series of scales which was laid (roof-like) upon 

 the succeeding row being hidden, and the pointed base 

 exposed. In some species the representation will 

 not resemble the markings of the butterfly, evidently 



