234 INDIEECT BENEFITS DEEIVED FROM INSECTS. 



aquatic insects. A large number of the land-bugs {Geoco- 

 risce Latr.) plunge their rostrum into the larvae of Lepidoptera, 

 and suck the contents of their bodies ; and Reduvius personatus, 

 which ought on that account to be encouraged, is particularly 

 fond of the bed-bug, as, according to Kuhn, is Pentatoma hi- 

 dens, six or eight of which, shut up in a room swarming with 

 the bed-bug, for several weeks, completely extirpated the 

 latter.^ 



But of all the insects that are locomotive and pursue their 

 prey in every state, none are greater enemies of their fellow 

 tribes than the Libellulina, and none are provided with more 

 powerful and singular instruments 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.^ 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 rapacious 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 pro- 

 ceedings of a species not uncommon here, Anax Imperator of 

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

 wards 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 Lihelhdina presume to ap- 



1 Naturforscher, St. 6. and Fallen, Hemipt. Suec. 142. quoted by Westwood, 

 Mod. Class, of Ins. ii. 486. 



2 Reaum. vi. 400. t. 36—38. 



