506 MOTIONS OF INSECTS. 



root devourers or tree-chafers (^Mclolontha, HopKa, he.) support themselves^ 

 like swarming bees, in the air, and over the trees, flying round in all 

 directions. The Brachyptera and DonacicE, in warm weather, fly off from 

 their station with the utmost ease ; — their wings are unfolded, and they 

 are in the air in an instant, especially the latter, as I have often found 

 when I have attempted to take them. None are more remarkable for this 

 than the Cicindelfe, which, however, taking very short flights, are as easily 

 marked down as a partridge, and afford as much amusement to the ento- 

 mologist as the latter to the sportsman. It is to be observed that many 

 insects in this order have no wings, and the female glow-worms neither 

 wings nor elytra. 



Many persons are not aware that the insects of the next order, the 

 Dermaptera, can fly; but earwigs (Forjicula), their size considered, are 

 furnished with very ample and curious wings, the principal nervures of 

 which are so many radii, diverging from a common point near the anterior 

 margin. Between these are others, which, proceeding from the opposite 

 margin, terminate in the middle of the wing. These organs, when at 

 rest, are more than once folded both transversely and longitudinally. 



Wings equally ample, forming the quadrant of a circle, and with five 

 or six nervures diverging from their base, distinguish the Strepsipterous 

 tribe. When unemployed, these are folded longitudinally.^ 



Probably in the next order (^Orthoptera) the tegmina, or wing-covers — 

 since they are usually of a much thinner substance than elytra — assist 

 them in flying. They are, however, quite covered by irregular reticula- 

 tions, produced by various nervures sent forth by the longitudinal ones, 

 and running in all directions. When at rest, the inner part of one laps 

 over that of the other ; but in different genera there is a singular variation 

 in this circumstance. Thus in Blatta, Phasma, and male Acridce, and 

 generally speaking, but not invariably, in Locusta, and Truxalis, the left 

 elytrum laps over the right ; but in Mantis, Mantispa, some female Acrida^ 

 Gryllus, and Gryllotalpa, the right is laid over the left. The wings in 

 this order, though always ample and larger than the tegmina, do not 

 invariably form a quadrant of a circle, falling often short of it. They are 

 extended by means of nervures, which, like so many rays, diverge from 

 the base of the wing ; and are intersected alternately by transverse ones, 

 which thus form quadrangular areas, arranged like bricks in a wall. When 

 at rest, they are longitudinally folded. The flight of these insects, as far 

 as it has been observed, much resembles, it is said, that of certain birds. 

 Ray tells us that both sexes of the house-cricket (GryUm domesticus) fly 

 with an undulating motion, like a woodpecker, alternately ascending with 

 expanded wings, and descending with folded ones.^ The field and mole- 

 crickets (Gryllus campestris and Gryllotalpa vulgaris), as we learn from 

 Mr. White^, — and, since the structure of their wings is similar, probably 

 the other Orthoptera, — fly in the same way. 



Hemipierous insects, with respect to their hemclytra, may be divided 

 into two classes. Those in which they are all of the same substance — 



1 Plate II. Fig. 1. It has been ascertained that the spurious elytra of these insects are 

 serviceable in their flight. As M. Latreille now allows this, he ought to have restored its 

 original namc; which he had altered, to this order. 



*■ Hist. Ins. 63. 3 Nat. Hist. ii. 82. 



