154 NEUROPTERA. 



as the anterior, or sometimes even larger, they are occasionally 

 much smaller, and may even be altogether wanting. 



736. The body of the Insects of this Order, which contains 

 the well-known Dragon-flies, May-flies, Ant-lions, White Ants 

 or Termites, and others, is generally prolonged, and destitute of 

 any very hard integument. These insects are of intermediate 

 size : few of them exceeding in dimensions the largest Dragon- 

 flies of this country ; whilst none exhibit the minuteness of some 

 Hymenoptera and Coleoptera. They differ in the character of 

 their metamorphosis, as well as in their adult structure ; for in 

 some the metamorphosis is complete, the larva undergoing a 

 marked change of form ; and in others there is not much differ- 

 ence, except in the absence of wings, between the larva and 

 perfect insect. By these differences the Order may be divided 

 into two sections ; in the first of which the insect is active 

 during the whole of its pupa state ; whilst in the second, it is 

 quiescent, except just before its last metamorphosis. The first 

 of these groups may again be subdivided into five families ; the 

 LIBELLULIDJE or Dragon-Jlies ; the EPHEMERID.E or Day-flies; 

 thePERLHXE or Stone-flies ; the TERMITID^: or White Ants; and 

 the PSOCID^E or Book-lice. In the first three of these, the larvae 

 and pupas are inhabitants of the water, and respire by means of 

 peculiar organs placed along the sides or at the extremity of the 

 abdomen ; whilst in other respects they nearly resemble the per- 

 fect insect. They creep out of the water to undergo the final 

 metamorphosis. 



737. Section I. The LIBELLULID^E, or Dragon-flies, are well- 

 known insects ; being easily distinguished by the slender form of 

 their bodies, their varied colours, their large gauze-like wings, and 

 the rapidity of flight with which they pursue other insects on 

 which they prey. They have a large head, ot rounded form, fur- 

 nished at its sides with two very large compound eyes, and with 

 three ocelli, situated upon its upper surface. Their antennas are 

 very small and bristle-shaped ; and the organs of their mouths 

 large and powerful. Most of this tribe frequent the neighbour- 

 hood of water ; and may be frequently seen skimming over the 

 surface of ponds or streams, in search of flies, gnats, and other 



