lJ-t STATES OF INSECTS. 



occasionally it bears no proportion whatever to it. This 

 is the case with the subcortical one from Brasil lately 

 mentioned. It is more commonly longer than broad ; 

 but in some, as in the larvae of carrion beetles (SilpJue), 

 the reverse of this takes place. Its shape varies from 

 triangular to orbicular, the mouth of the animal forming 

 the vertex of the triangle. In some larvae of Hemerobii, 

 however, the head is narrowest behind. That of the grub 

 of a gnat noticed above [Corethra crystallina) forms a 

 kind of sharp horn or claw, terminating the body ante- 

 riorly a . The contour of the head of larvae is usually 

 intire and unbroken ; but in the caterpillars of some Lepi- 

 rlopfera, as the butterfly called thegrand admiral [Vanessa 

 Atalanta), the Glanville fritillary (Melitcea Cinxia\ &c. 

 it is divided into two lobes b . In the Brazil flat larvae it 

 is trilobed, each lateral lobe being divided into three 

 smaller ones : in which circumstance it somewhat resem- 

 bles the head of some subcortical Cimicida. Although 



o 



the part we are treating of is generally without horns., 

 yet in some tropical butterflies of the tribe of NympJiales, 

 it is singularly armed with them. Thus Papilio Anchises 

 is distinguished, according to Madame Merian c , by two 

 in the occiput, which it has the power of retracting. In 

 the purple highflier {Apatura Iris), a British species, the 



a Reaum. v. /. vi.f. 7. i.e. 



b In fact, in almost all Lepidopterous larvae the head may be re- 

 garded as divided into two lobes or eye-shaped portions, which in- 

 clude in the angle formed by their recession anteriorly from each 

 other, the nasus (clypeus F.), the labrum, and other instruments of 

 manducation. Posteriorly these lobes generally come into contact; 

 but I have a specimen in which there is a narrow space between 

 them. 



c Ins. Surinam, t. xvii. 



