INDIRECT BENEFITS DERIVED FROM INSECTS. 273 



of assault. In the larva and pupa states, during which 

 they live in the water and prey upon aquatic insects, 

 they are furnished with two pair of strong jaws, covered 

 by a kind of mask armed with a pair of forceps or claws, 

 which the animal has the power of pushing from it to 

 catch any thing at a distance a . When an aquatic insect 

 passes within its reach, it suddenly darts forth the mask, 

 opens the forceps, seizes the unfortunate victim, and 

 brings it within the action of its jaws. 



When they assume the imago state, their habits do 

 not, like those of the white ants, become more mild and 

 gentle, but on the contrary are more sanguinary and ra- 

 pacious than ever ; so that the name given to them in 

 England, " Dragon-flies," seems much more applicable 

 than "Demoiselles," by which the French distinguish 

 them. Their motions it is true are light and airy; their 

 dress is silky, brilliant and variegated, and trimmed with 

 the finest lace : — so far the resemblance holds ; but their 

 purpose, except at the time of love, is always destruction, 

 in which surely they have no resemblance to the ladies. 

 I have been much amused by observing the proceed- 

 ings of a species not uncommon here, Anax hnperator of 

 Dr. Leach. It keeps wheeling round and round, and 

 backwards and forwards, over a considerable portion of 

 the pool it frequents. If one of the same species comes in 

 its way, a battle ensues ; if other species of Libellulidce 

 presume to approach, it drives them away, and it is con- 

 tinually engaged in catching Phryganeae and other in- 

 sects (for the species of this tribe all catch their prey 

 when on the wing, and their large eyes seem given them 

 to enable them the more readily to do this,) that fly over 



1 Reamn. vi. 400. t. 36—38. Plate XVI. Fig. 5. a, 

 VOL. I. T 



