iJ74 INSECTA. 



The antennas vary and are always niultiarticulated. Two ocelli 

 are observable in several species, but concealed between the scales *. 

 Tlie three 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 their inner margin. At the base of 

 each of the superior Avings is a kind of epualette, prolonged poste- 

 riorly, that corresponds to the piece called tegula in the Hymenop- 

 tera. As it is more developed here, I will call \i pteri/goda. The 

 abdomen, composed 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 se- 

 veral females, however, as in Cossus, the last rings become nar- 

 rowed, 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 abdo- 

 men of the former is terminated by a kind of flat forceps which con- 

 tains the penis. 



The females usually deposit their ova, frequently very numerous, 

 on the vegetable surfaces which are to nourish tlieir larvse, and soon 

 after perish. 



The larvse of Lepidopterous Insects are well known by the name 

 of caterpillars. They have six squamous or hooked feet, which cor- 

 respond to the legs of the perfect Insect, and from four to ten addi- 

 tional membranous ones, the two last of which are situated at the 

 posterior extremity of the body, near the anus ; those which liave 

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

 gression, geonietrce. They cling to the plane of position Avith their 

 squamons feet, and then, elevating the intermediate segments of the 

 body in the form of a ring or buckle, approximate the tAvo hind feet 

 to the preceding ones, disengage the latter, liold on Avith the last feet, 

 and move their body forAvards to recommence the same operation. 

 Several of these geometrne, Avhen at rest, remain fixed to the 

 branches of plants by the hind feet alone, Avhcre, in the form, colour and 

 direction of their body they resemble a twig ; they can support them- 

 selves in this position for a long time, without exhibiting tlie 

 slightest symptom of life. So fatiguing an attitude must require 

 prodigious muscular force, and in fact Lyonet counted four thousand 

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

 * According; to an observation maie by Dalman, they do not exist in the Diurnee. 



