397 



LEPIDOMELANE. 



LEPIDOSTROBI. 



LEPIDOMELANE. [MICA.] 



LEPIDOPH YLLUM. Fossil Leaves which occur in the coal forma- 

 tion are thus named by M. Brongniart. They appear to have been 

 sessile, simple, entire, lanceolate or linear, traversed by a single simple 

 midrib, or three parallel nervures, and without secondary nervures. 

 (Some of these belong to Lepidodendron, others to Stigmaria.) 



LEPIDO'PTERA, one of the Orders into which Insects are divided, 

 called Glostata by Fabricius. 



This order is composed of those insects which are commonly known 

 by the names Butterflies and Moths, and which possess four wings, 

 usually of large size, and covered with a multitude of minute scales, 

 which to the naked eye appear like powder. The nervures of the 

 wings are not very numerous, and are disposed chiefly in a longitudinal 

 direction : a small tippet-like appendage is situated on each side of 

 the thorax at the base of the wings, which appendages are called by 

 Latreille Pterygoda. The antennae are almost always distinct, and 

 are composed of numerous minute joints. The parts of the mouth 

 are formed into a proboscis fitted for extracting the nectar from 

 flowers, or conveying other juices to the ccsophagus. This proboscis, 

 when not in use, lies spirally folded beneath the head and between 

 two palpi covered with hair, which are usually directed forwards and 

 upward*, and which represent the labial-palpi. The proboscis is 

 called, in these insects, Antlia by Messrs. Kirby and Spence, Spiritrompe 

 by Latreille, and Lingua according to the nomenclature of Fabricius ; 

 and is composed of two sub-cylindrical tubes, which vary greatly in 

 length in the different species of Lepidopterous Insects, and between 

 which there is an intermediate one, formed by their junction, which 

 ia effected by means of a series of hooka inosculating one with 

 another like the lamiiiie of a feather. It is through this central tube 

 that the juices are conveyed, tbe lateral tubes being intended, as it is 

 supposed, for the reception of air ; they are called by Messrs. Kirby 

 and Spence Solenaria, a name however which is not wanted, since the 

 two tubes in question represent the maxillae, and are furnished with 

 minute maxillary-palpi at their base. The mandibles and labrum in 

 these insects are reduced to mere rudiments. The head, thorax, and 

 abdomen are always more or less covered with hair ; the former, 

 besides the ordinary compound eyes, is sometimes furnished with 

 simple eyes or stemmata ; these however are generally hidden by the 

 hair of the head, and, according to M. Dalman, do not exist in the 

 diurnal Lepidoptera. Of the three segments of which the thorax is 

 composed, the first is usually distinct, though small ; the others are 

 confluent ; the scutellum is triangular, the apex of the triangle point- 

 ing towards the head. The abdomen is composed of six or seven 

 distinct segments, and is attached to the thorax only by a small portion 

 of its diameter. There are only two kinds of individuals, males and 

 females. 



The principal modifications of the larvae, or caterpillars, of Lepi- 

 dopterous insects are noticed in the article IXSKCTA. 



The food of the larvae almost always consists of vegetable substances, 

 generally the leaves of plants ; some live hi rotten, or rather, dead 

 wood, upon which they feed; others feed upon animal substances, and 

 are very destructive to furs, woollen goods, feathers, &c. ; and the 

 larva of a species of moth (the honeycomb moth, Gallei-ia, cereana) 

 subsists upon wax, living in bee-hives.* 



The pupae, or chrysalises, are incapable of eating or locomotion, 

 and are termed obtected ; they usually approach somewhat to an oval 

 form, but are pointed more or less at the posterior extremity. The 

 shape of the pupae however varies much according to the species ; 

 and those of hutterflies-often present numerous angular projections, 

 and sometimes exhibit brilliant metallic colours. The parts of the 

 perfect insect, such as the head, thorax, segments of the abdomen, 

 wings, and legs, can be distinctly traced. Various m&difications of 

 the pupa state of the present insects are noticed in the separate 

 articles on species which are described. 



Latreille divides this order into three principal groups, according 

 with the three Linnwan genera Papilio, Sphinx, and Phakena. To 

 the first group he applied the name Itiurna; CrepuicuZaria is used to 

 designate the second ; and the third group, or that corresponding to 

 Phalcena of Linnaeus, is called by Latreille Nocturna. 



The group Lepidoptera Dim-no, comprises those species which fly 

 by day, called Butterflies, in which the antenna} are terminated by n 

 knob, or at least somewhat suddenly thicker at the extremity ; the 

 anterior margin of the posterior wings is simple ; the wings are 

 usually erect when the insect is in a state of repose ; the larva) have 

 16 legs ; the chrysalises are always naked, attached by the posterior 

 extremity, so that the head hangs downwards, and have usually 

 angular projections. 



The Lepidoptera, Crepuscularia are distinguished by the antenna) 

 being gradually thicker from the base towards the extremity, and form- 

 ing a prismatic or fusiform club ; the extreme tip is slender, pointed, 

 and often recurved. The wings are in a horizontal position when at rest, 

 or a little inclined ; the posterior wings have a rigid spine at the ante- 

 rior margin, which i received into a hook on the under surface of 

 the superior wings. The caterpillars have 16 feet, 6 of which are 



* Thl larva forma galleries in the honeycomb, which arc invariably inclosed 

 by a strong silken web, serving to protect it from the bees ; and as the moths 

 increase rapidly in number, tbe hive is of necessity soon deserted by its proper 

 inhabitant!. 



thoracic, 8 abdominal, and 2 anal ; and many of them have a horn- 

 like process on the upper side of the last segment. The pupa; are 

 never angular like those of butterflies, but are generally smooth, and 

 sometimes furnished with small spines. The perfect insects generally 

 fly in the morning, evening, or afternoon. 



The Lepidoptera Nocturna have the antennae setaceous, or diminish- 

 ing gradually from the base to the apex, often serrated or pectinated, 

 especially in the male sex : the wings during repose are horizontal or 

 deflexed, and sometimes convoluted and inclosing the body; the 

 posterior wings, as in L. Crepuscvlaria, have a rigid seta on their 

 anterior margin, which hooks into a corresponding groove in the 

 anterior wings. The larva; differ much in form, and in the number of 

 feet they possess, varying from 10 to 16. They frequently inclose 

 themselves in a cocoon before assuming the pupa state. The pupa is 

 most frequently smooth, but is sometimes furnished with spines, and 

 in some instances it is hairy. 



The perfect insect almost always flies by night or after sunset. In 

 some species the females are apterous. 



LEPIDOPUS. [T-ENIOIDES.] 



LEPIDOSTROBI. Detached petrified cones which are scattered 

 through the various strata of the Coal Formation have been thus 

 named. They are obviously organs of fructification, and have there- 

 fore belonged to some of the arborescent plants whose remains they 

 accompany. Such of them as are preserved in the nodules of iron-stone, 

 or are otherwise mineralised without pressure, alone offer the means of 

 ascertaining to what existing families of plants they are most nearly 

 allied ; for in those that are crushed flat in the shales the internal struc- 

 ture is wholly destroyed. Many of the better-preserved specimens have 

 been sliced, polished, and examined with the greatest care ; but this ex- 

 pensive operation has hitherto thrown little light upon the true nature 

 of the objects investigated. This is owing to the fact that the three 

 conditions necessary for their complete illustration have never been 

 displayed by one specimen, and the most important point, the nature 

 of the organs of fructification, has hitherto wholly escaped observation 

 in all. Every one being an aggregation of organs of some kind it 

 becomes necessary to ascertain, not only the arrangement of these 

 organs, but the nature of the tissues composing them, and their 

 contents, before satisfactory conclusions can be drawn as to their 

 relationship to any of the vegetable remains they accompany, or to 

 whatever existing order of plants they are allied. The three necessary 

 conditions are these : 



1. The arrangement of the individual organs of fructification, of 

 which the cone is an aggregation, and the nature of the scales sup- 

 porting them. These are characters sometimes displayed on the 

 fracture of the specimen by ordinary means, though rarely, from the 

 parts appearing to have suffered partial decay previous to or during 

 petrifaction. The imbricating apices of the scales, which lie over one 

 another like those of a pine cone, are generally removed with the 

 matrix wherein the fossil is embedded. 



2. The tissues, or anatomical structure of the various organs 

 composing the cone : namely, of the central axis, which is a continua- 

 tion of the stem of the plant ; of the scales, which being inserted 

 into the axis support the individual male or female organs ; and of 

 the latter themselves. These tissues can only be displayed by slicing 

 fossils in the very best state of preservation, and in such as are 

 changed into a more or less transparent mineral. Specimens of this 

 description are exceedingly rare. 



3. The two preceding considerations are secondary to the remaining 

 one the nature of the contents of the cones. There may be stamens 

 or male organs ovaria or female ones or, lastly, capsules containing 

 reproductive spores (which are peculiar to plants having no sexual 

 system) ; for these three kinds of organs all occur arranged in the 

 form of cones, undistiuguishable from one another by any external 

 marks. Up to the present time no carboniferous fossil cone has ever 

 been known to supply this great desideratum, without which wo can 

 arrive at no exact conclusion as to whether these curious objects are 

 clusters of flowers or fruits, or are the spore-bearing organs of 

 floweiiess vegetables, as mentioned above. 



Specimens of Lepidostrobi are mostly found in seams or nodules of 

 clay iron-stone, and are very highly mineralised, sometimes containing 

 crystals of iron, and the cavities in their substance being filled with 

 white carbonate of lime and magnesia. Those which are most com- 

 plete always form the nuclei to nodules of clay iron-stone ; others 

 again, including all in which the spores are preserved, have occurred 

 as broken frustules within stems of Lcpidodendrou eleyans and other 

 species of that genus. Usually the fragments of Lepidoslrobi are not 

 more than half an inch long, and very frequently are mere discs ; so 

 that though there is often the appearance of one several inches long, 

 and traversing the whole length of the fragment of Lepidodendron, it 

 will generally be found that this is owing to two being placed each at 

 an extremity of the truncheon, and opposite to one another. [See 

 Figure, COAL PLANTS.] That all were exceedingly brittle cannot be 

 doubted, for no modern cone of any natural order could be broken 

 up into the shallow discs which many of these fossils present. It is 

 difficult to account for the presence of these fragments of Lepido- 

 strobi in the stems of Lepidodendron ; we can but conjecture that the 

 trunks of the latter were erect stumps, whose interior was hollowed 

 out by decay that these stumps were covered with water in which 



