CHAPTEE XVIII 



AMPHIBIOUS NEUROPTERA CONTINUED ODONATA, DRAGON-FLIES 



Fam. VI. Odonata Dragon-flies. 



(libellulidae of some authors) 



Mongate Insects with very motile head and large eyes, loitli small 

 and inconspicuous antennae ending in a hristle ; luith four 

 elongate tuings sub-equal in size and similar in texture, of 

 j)apyraceous consistency and having many veinlets, so that 

 there exists a large number of small cells. All the legs placed 

 more anteriorly than the loings. The earlier stages of the 

 life are aquatic ; there is great change in the appearance of 

 the individual at the final ecdysis, but there is no pupcd 

 instar. 



The dragon-flies form a very natural and distinct group of 

 Insects. All the species are recognised with ease as belonging 

 to the family. They are invariably provided with wings in the 

 perfect state, and many of them are amongst the most active of 

 Insects. Their anatomy is, in several respects, very remarkable. 



The head is large and is concave behind ; it is attached to 

 the thorax in such a way that it rotates on two cervical sclerites 

 that project forwards, and in some cases almost meet in a point 

 in front ; hence it possesses extreme mobility, the power of 

 rotation being very great. 



The eyes are always large ; in some cases they are even enor- 

 mous, and occupy the larger part of the area of the head: the 

 upper facets of the eye are in many cases larger than the 

 lower, and in a few forms the line of division is sharply marked 

 transversely. There are three ocelli, which, when the size of 

 the compound eyes is not too great, are placed in the usual 



