INSECTS. 233 



nearly the whole of the Linnaean orders Aptera and Hemiptera; 

 the second comprises, with few exceptions, the whole of the Lin- 

 naean orders, Coleoptera, Lepidoptera, Hymenoptera, Diptera, 

 and the greater portion of the Neuroptera. 



Previous to their change the larvae exhibit appearances of the 

 greatest anxiety and restlessness. They cease to eat, wander 

 about with instinctive care, seeking for holes in the earth, chinks 

 in trees, crevices in walls, or other places for their temporary re- 

 pose. Many penetrate the ground to the depth of several inches; 

 the grubs of the gad-fly creep out of the backs of the cattle 

 and drop on the ground, or are carried by the animal licking it- 

 self into its mouth and through its intestines ; and the various 

 aquatic larvae leave the water for an element more suited to their 

 future existence. The Coccinetlce and others fix themselves by 

 the anus under leaves or twigs ; others suspend themselves by a 

 silken thread ; and a very great number inclose themselves in 

 cases or cocoons composed of silk and other materials, to under- 

 go their final change. 



The second form in which insects appear is the pupa or nym- 

 pha state. In this the number of the exterior organs of the 

 animal are augmented or developed anew. Linnaeus arrang- 

 ed the forms under which insects appear in this state under 

 five heads, viz. 1 . Pupa completa ; where the larva and pupa 

 are capable of motion, take food, and much resemble the perfect 

 insect; 2. Papa semicompleta ; where the pupa moves, eats, 

 and has elytra, as in the grasshoppers, dragon-flies^ &c. ; 3. 

 Pupa incompleta ; with motionless feet and wings, as many 

 beetles, bees, and ants ; 4. Pupa obtecta, with a coriaceous skin, 

 so that the thorax, abdomen, and other members can be distin- 

 guished, as in butterflies ; 5. Pupa coarctata , of an oblong 

 cylindrical form, with no part of the body visible. The whole 

 however, may be reduced under two heads, first, those in which 

 the transformation is partial ; and secondly, those in which it 

 is complete. 



The influence which the partial metamorphosis exercises on 

 the body is not sufficiently powerful to destroy the typical form 

 proper to the species, and is modified only by slight alterations. 

 An experienced eye which has seen the animal in its first stage 

 of life can still recognize the individual. The principal change 

 takes place in the exterior members, and particularly in the or- 



