ARTICULATES. 603 



Of the second kind, are those which undergo a complete met- 

 amorphosis. These include those in which no trace of a future 

 insect can be perceived, as in the Fly, Musca, and others of the 

 dipterous or two-winged insects; those in which the thorax and 

 abdomen are distinct, and enclosed in a horny case, as in the 

 Butterflies ; and those in which the parts are covered by a mem- 

 brane, but distinct, as in the order Hymenoptera, and some of 

 the Two-winged Insects. 



In the Coleoptera, Lepidoptera, Hymenoptera, Diptera, and ' 

 some of the Neuroptera, the pupa state is one of complete inac- 

 tivity as to all manifestations of animal life, while yet the interior 

 formative processes are carried on with extraordinary energy. 

 In the egg, the development in the case of these insects, was only 

 carried far enough to enable the larvae to come forth, and to 

 obtain their own food. In the pupa state, it is continued at the 

 expense of the nutriment which they had collected and stored 

 up within their bodies, so that the passage into the pupa state 

 might almost be compared to a second entering into the egg. 



Of those which are not, like the Silk-worm, protected by a 

 cocoon, some suspend themselves by their -hind extremity ; others, 

 as the Butterfly, Papilio, attach themselves, with the head above, 

 and a thread around the body to keep it in its position. Some of 

 these hanging pupae exhibit bright colors and golden spots, whence 

 the name Chrysalis, (from Gr. chrusos, gold.) 



In the Ant-tribes, the Neuters do not acquire wings. Some 

 of them, which are two or three times as large as the rest, and 

 somewhat differently formed, are named "soldiers," it being 

 their special office to defend the nest, rather than to nurture 

 young; and in the White Ants, Termites, the "soldiers" appear 

 to be pupae arrested in their development, while the "workers" 

 have the characters of permanent larvae. 



The period of inactivity in the pupa state, greatly varies in 

 duration ; some insects remaining inactive for years or months, 

 while others pass through that state in a few days or hours, and 

 reach the fourth or last stage, when the insect is called Imago, 

 (Lat. image.) Now, having laid aside its mask, and cast off its 

 swaddling bands, it becomes a proper image or representative of 

 its species. Whenever an insect is spoken of without the restrict- 

 ing terms larva and pupa, it should be remembered, the imago 

 state is meant. In this state, the three principal parts of head, 

 thorax, and abdomen, are distinctly perceptible ; the insect now 

 eats much less food than when in its first state. Some, indeed, 

 live so short a time as to need no food, as the Silk- worm and the 



