548 



INSECTA. 



the rudiments of the generative organs are further developed, and it 

 becomes moro and more like the winged insect. In the simplest case- 

 the mode of life and the organization of the young larvae closely 

 resemble those of the sexually adult animal, as for instance in the 

 Hemiptera and Orthoptera genuina, but in other cases the adult and 

 larva may differ considerably, although not so much so as in insects 

 with complete metamorphosis ; for instance, the larvae of the 

 Ephemeridae and the Libellulidae live in another medium and increase 

 in size under different conditions of nourishment (fig. 456). 



The metamorphosis is only said to be complete in those forms in 

 \vhich the larva passes through a quiescent stage, in which it is 

 known as a pupa and does not take nourishment. With this stage 



FIG. 457. Metamorphosis of Sitaris kumeralii (after Pabre). a, First larval form, b, Second 

 larval form, c, Pseudo-pupa, d, Third larval form, e, Pupa. 



the larval life ends and the life of the winged insect (Imago) begins. 

 The larvae of insects with complete metamorphosis differ from the 

 sexual animal to such an extent in mode of life and nourishment, in 

 the form of the body and in the whole organization, that though the 

 parfes of the body peculiar to the winged insect are prepared and 

 established in larval life, yet a longer or shorter period of quiescence, 

 in a certain sense a second embryonic period, seems necessary, during 

 which the essential alterations of the internal organs, as well as the 

 consolidation of the newly-established external parts, are effected 

 (hypermetamorpliosis, Meloidae, fig. 457). 



In the form of their body and the homonomous segmentation, 

 the larva; recall Annelids, with which they also often have in 



