156 STATES OF INSECTS. 



change of skin, is deprived of its bent thorn-like points 

 which attend it when young a . It is remarkable that 

 these last larvae, when just excluded from the egg, are 

 also entirely destitute of these appendages; they soon, 

 however, appear, from slight elevations which mark their 

 situation, and rapidly acquire their usual form b . Changes 

 of a similar kind, hitherto unobserved, may probably 

 take place in other species. 



iii. Figure. I am next to consider the general figure or 

 shape of larvae. All of them, with but few exceptions c , 

 agree in having a body more or less constricted at inter- 

 vals into a series of rings or segments ,- usually in num- 

 ber, twelve ; often nearly equal in length, but sometimes 

 in this respect very dissimilar d . The general outline or 

 shape of the body is extremely various : most frequently 

 it approaches to cylindrical, as in most of the caterpillars 

 of Lepidoptera, and of the Hymenopterous tribe of saw- 

 flies [Tenthredo L.). The next most common figure is 

 that more or less oblong or oval one, sometimes ap- 

 proaching to conical, found in many of the larvae usually 

 called grubs; such as those of the weevil {Curculio L.) and 



a Ro's. iii. t. Ixviii./. 1. Meinecken Naturf. vi. 120. 



b Ibid. xiii. 175. 



c In the larva of Tenthredo Cerasi L., and some others, no traces 

 of segments are to be seen ; and in many coleopterous and dipterous 

 ones the folds of the skin prevent the segments from being distinctly 

 perceptible. 



d Reaum. ii. 361 . In the larva of a small common moth often met 

 with in houses {Aglossa pinguinalis), every segment is divided into two 

 parts, and underneath has two deep folds, by means of which these two 

 parts can separate to a certain point, or approach again, according to 

 circumstances. Thus Providence has enabled them to prevent their 

 spiracles from being stopped by the greasy substances on which they 

 often feed. N. Diet. d'Hist. Nat. i. 208. 



