THE WINGS OF INS ECTS. 27 



some dragon flies, which may be seen for hours to- 

 gether shooting hke flashes of hght, backwards and 

 forwards, in search of small insects for food, over a 

 pool of water; Leeuwenhoek states that he saw a 

 swallow chasing a dragon fly in a menagerie 100 feet 

 long, and that the bird was unable to catch it.* It 

 may be observed here, as a curious fact, that dragon 

 flies can fly backwards and sideways as well as forward. 



Some insects have to procure their food by burrow- 

 ing in the ground, by searching among stones, or about 

 the roots and footstalks of plants, and as they are 

 often obliged to mount into the air, for transit and 

 other purposes, wings are necessary ; but these delicate 

 organs would soon be destfoyed by the insects' way of 

 life were not some provision made for their defence, 

 this is accordingly done, and we see that beetles, &;c. 

 have a pair of hard wing cases, underneath which the 

 wings lie folded up until they are required for flight : 

 in large beetles (such as the cockchafer, and the black 

 beetle that flies about in Spring and Autumn evenings 

 with a buzzing noise) the wing has but two folds, one, 

 longitudinally, near the tip and another, transversely, 

 near the middle ; in the rove beetles (viz, those resem- 

 bling in shape one abundant near Plymouth and called 

 the devil's coach horse) which have short wing cases, 

 the wings have several folds, that they may lie in a 

 small space ; in the earwig (a brown insect, with a 

 pair of nippers at the tail, which may be found among the 

 decayed leaves of nettles) the wings, which are most 

 beautifully nervured, have three transverse folds and 

 several longitudinal ones like those of a fan. 



Many beetles find their food at the bottom of pools 

 and streams of water, and they are also furnished with 

 wings in order to move from one place to another, as 

 the pool may be dried up or cease to afford them nu- 

 triment. If the wing case of one of these beetles be 

 lifted carefully up the wings may be seen beneath per- 

 fectly dry and prepared for flight : one of the most cu- 



* Leeuwenhoek, Epist. 6. Mart, 1717. 



