EARLY STATES OF DRAGON-FLY. 149 



liarly aquatic. The eggs are deposited upon aquatic plants, and 

 the larvaa are thus produced in the element in which they are at 

 first to reside. The head of the pupa is remarkable for the 



FIG. 371. A, the pupa with its mask. B, the same with the mask closed, and 

 discharging a current of water. 



singular form of the portion which takes the place of the lower 

 lip; this is a kind of mask, composed of several pieces, and cover- 

 ing the mandibles, maxillae, and nearly all the under side of the 

 head, when it is closed together ; but being capable of extension 

 and unfolding, and being furnished with a pair of sharp claws at 

 its upper part, so as to become the instrument by which the 

 animal seizes its prey. The posterior end of the abdomen, in the 

 early state of the Dragon-flies, is usually the seat of the respi- 

 ratory function. This is commonly performed by means of three 

 leaf-like membranous organs, which are situated inside the extre- 

 mity of the intestine, or sometimes within a sort of prolonged 

 pyramidal tail ; in using these, the animal draws a supply of 

 water into the rectum ; and then forces it out violently, by which 

 acl it also impels itself through the water. The succession of 

 jerks thus produced, is the chief means of locomotion of the 

 larvae of the Dragon-flies, and serves to distinguish them from all 

 other aquatic larvae; so that they are very easily recognised. Several 



