LEPIDOPTERA. 435 



segments, of which the trunk of the hexapoda is composed, are united in one 

 single body; the first is very short, and the two others are confounded 

 together. The scutellum is triangular, but the apex is directed towards the 

 head. The wings are simply veined, and vary in size, figure and position ; 

 in several, the inferior ones are plaited longitudinally near the inner margin. 

 At the base of each of the superior wings is a kind of epaulette, prolonged 

 posteriorly, that corresponds to the piece called tegula in the Hymenoptera. 

 As it is more developed here, I will call it pterygoda. The abdomen, com- 

 posed of from six to seven annuli, is attached to the thorax by a very small 

 portion of its diameter, and presents neither sting nor ovipositor analogous to 

 that of the Hymenoptera. In several females, however, as in Cossus, the last 

 rings become narrowed, and extended to form an oviduct resembling a 

 pointed and retractile tail. The tarsi always have five joints. There are 

 never more than two kinds of individuals, males and females. 



The females usually deposit their ova, frequently very numerous, on the 

 vegetable surfaces which are to nourish their larvae, and soon after perish. 

 The larvae of Lepidopterous insects are well known by the name of 



caterpillars. They have six squamous or 

 hooked feet, which correspond to the legs 

 of the perfect insect, and from four to 

 ten additional membranous ones, the two 

 last of which are situated at the posterior 

 extremity of the body ; those, which have 

 but ten or twelve in all, have been called, from their mode of progression, geo- 

 metrce. Several of these geometrae, when at rest, remain fixed to the branches 

 of plants by the hind feet alone, where, in the form, colour, and direction of 

 their body, they resemble a twig ; they can support themselves in this position 

 for a long time, without exhibiting the slightest symptom of life. So fatiguing 

 an attitude must require prodigious muscular force, and, in fact, Lyonnet counted 

 four thousand and forty-one muscles in the caterpillar of the Cossus ligniperda. 

 The body of these larvae is generally elongated, almost cylindrical, soft, 

 variously coloured, sometimes naked, and sometimes covered with hairs, 

 tubercles, and spines. It is composed of twelve segments or annuli, exclusive 

 of the head, with nine stigmata on each side. Their head is invested with a 

 corneous or squamous dermis, and presents on each side six shining granules, 

 which appear to be ocelli ; it is also furnished with two very short and conical 

 antennie, and a mouth composed of strong mandibles, two maxills, a labium, 

 and four small palpi. The silk they employ is elaborated in two long and 

 tortuous internal vessels, of which the attenuated superior extremities termi- 

 nate in the lip. A tubular and conical mammilla is the spindle through 

 which the threads are spun. 



Most caterpillars feed on the leaves of plants; some gnaw their flowers, 

 roots, buds, and seeds; others attack the ligneous or hardest part of trees, 

 softening it by means of a fluid which they disgorge. Certain species attack 

 our woollens and furs, thereby doing us much injury: even our leather, 



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