360 



INSECTA. 



The last stage of larval life is always the pupal stage, which, 

 in the form of the body, the development of the limbs, and the 

 structure of the mouth-parts, resembles the imago. In this stage 

 the Insects cease to take nourishment, and also, as a rule, the capacity 

 of locomotion is lost (quiescent or resting pupa). The pupa is often 

 enclosed in a cocoon spun by the larva. If the limbs of the pupa 

 stand out freely from the surface of the body it is known as free- 

 limbed (pupa libera, the exarate, incomplete, or sculptured pupa). 

 In other cases the limbs which, in the resting pupa, are held closely 



pressed against 

 the ventral side, 

 become free imme- 

 diately after the 

 casting of the 

 larval integument, 

 but soon become 

 glued to the sur- 

 face of the body 

 by the hardening 

 of a tough secre- 

 tion, so that their 

 outlines are less 

 distinct (Lepidop- 

 tera and many 

 Diptera). Such 

 forms are known 

 as mummy pupae 

 (obtected, larcate, 

 or signate pupa, 

 chrysalis). Among 

 the Diptera it 

 often happens that the pupa remains surrounded by the last larval 

 integument (barrel-like pupa, pupa coarctata). 



The number of moults undergone by an insect with complete 

 metamorphosis is limited, and never attains that found among the 

 Homomorpha (Ephemeridae). 



Neuroptera. The larvae of the Sialidac, which in appearance resemble many 

 Coleopteran larvae, have mouth-parts adapted for biting, like those of the 

 imago. The larvae of the Megaloptera, on the contrary, have their mouth-parts 

 singularly transformed for sucking the juices of their prey ; the mandibles have 

 a furrow on the lower side, and, with the maxillae, form on each side a sucking 

 tuue. Some of these larvae are elongate and recall the Coleopteran larvae 



Fm. 17S. — .4, Perlid larva, lateral aspect 

 (after Geaber). k, ^ill-tufts ; st, stig- 

 mata. B, larva of Perla bicaudata (after 

 Westwood). 



