36'4 



ORDERS OF PTILOTA. 



ORDER VI. — NEUROPTERA. 



This order belongs to the division having the mouth 

 formed with mandibles for mastication, and chiefly dis- 

 tinguished by the structure of the wings, which are naked ; 

 that is, not inclosed by elytra or tegmina, but often having 

 the anterior and posterior pairs of equal size, and fm'nished 



Dragoa-fly. 



with a great number of nerves, which gives the wings the 

 appearance, under the microscope, of a piece of the most 

 beautiful net-work ; whence, indeed, the name of the order 

 is derived, neuron signifying a nerve, and pteron a wing. 

 The membrane inclosed between these nerves is very fine 

 and transparent, often exhibiting a reflection of the prismatic 

 tints, or marked with spots or bands of various colours. 

 The situation of these organs during repose is various ; in 

 some they are horizontally extended at right angles from 

 the body, as in the larger Libellulidm; in others, as in the 

 smaller species of the same family, their inner surfaces are 

 applied against each other ; whilst in the Perlidce they lie 

 flat upon the back, or are deflexed at the sides like the roof 

 of a house, as in Hemerobius, Psocus, &c. In many species 



