THE CRICKETS 



963 



than himself in captivity, we are justified 

 in supposing that, in the adult state at 

 least, he is largely carnivorous, and that 

 he sits at the entrance of his burrow 

 waiting for such unwary insect travellers 

 as may alight on it, or cross it. 



This supposition is strengthened by the 

 rudimentary development of the Field 

 Cricket's flight wings. The power of 

 flight in insects is in close relation to their 

 natural food supply, and to the means 

 of communication between the two se.xes. 

 In the case of Field Crickets, the latter 

 is assured by their gregarious character, 

 coupled with the males' power of stridu- 

 lation. The folded flight wings of all 

 British Crickets present the appearance 

 of narrow twisted thongs, which, as a 

 rule, project beyond the covering afforded 

 by the wing-covers, and which may project 

 (this is often the case with the Mole 

 Cricket) in a downward curve beyond the 

 hind extremity of the body. Since they 

 are not only folded but rolled, their 

 arrangement at rest is remarkably like 

 that of a rolled-up umbrella. They may 

 be easily spread out with a paint-brush 

 on a moistened slip of glass, and it will 

 then be found that they have a character- 

 istic form which may be described as 

 semi-heart-shaped. 



I am doubtful as to whether the ex- 

 panse of a Field Cricket's wings is sufficient 

 to give him the power of true flight. 

 Gilbert White describes the flight of the 

 House Cricket — who, it should be noted, 

 has much larger wings and a proportion- 

 ately slighter body — as a wave motion : 

 " volatn nndoso, in waves or curves, like 

 woodpeckers, opening and shutting their 

 wings at e\'ery stroke . . . always rising 

 or sinking " ; and says that tlie flight of 

 the Mole Cricket is accom])lished in a 

 similar way. It is possible that a suit- 

 able disposition of the wing-covers may 

 assist the progress of both insects, and 

 I may perhaps mention in this connection 

 that the common orange and black 

 Burying Beetle almost inverts his elytra 

 in flight so that their concave portion is 

 uppermost. 



The stridulation of Crickets is effected, 

 like tliat of Long-horned Grasslu)pj)ers. 

 by the friction of the wing-covers against 

 one another ; but the wing-covers of 

 Crickets are far more highly specialised 



than those of Grasshoppers. Both right 

 and left are of the same pattern, and 

 apparently interchangeable in position, 

 the left being perhaps most frequently 

 uppermost. A remarkable and character- 

 istic feature of them is that they are 

 divided into two distinct planes, the lower 

 portion of each being parallel to the in- 

 sect's side, while the upper portion, bent 

 away from it almost at right angles, lies 

 upon the insect's back. It is this upper 

 portion which is employed as an instru- 

 ment of music. The principal nervures 

 on it may be said to radiate from a point 

 on its inner edge close to the base, which 

 is surmounted by a tuft of bristling hairs. 

 From this hair-tuft, taking the Field 

 Cricket as the t3'pe, a stout nervure 

 leads diagonally across the horizontal 

 portion of the wing and, towards the end 

 of its course, borders a transparent oval 

 disc, the main sounding-board, which is 

 about one-eighth of an inch in diameter. 

 From the same point two nervures run 

 directly across the horizontal portion, but 

 before reaching its outer edge turn sharply 

 towards the base. A portion of the 

 hindermost of these is notched like a 

 round file. 



As can be seen from the illustration, 

 the nervures at the tip of the wing form 

 a meshwork, but on the remainder of the 

 horizontal portion they branch into bold 

 and often symmetrical loops and curves 

 which enclose considerable areas of mem- 

 brane. 



In stridulating the Field Cricket ducks 

 his head, raises his wing-covers at an angle 

 of about 45°, and shudders them together 

 so that the under surface of the one 

 brushes lightly against the upper surface 

 of the other. Tliis brings the round-file 

 nervure into play against the nervures 

 of the wing-cover beneath it, which in 

 turn convey the vibration to the mem- 

 branes which they enclose. The sum of 

 the vibrations induced in the membranes 

 of both wings is the Cricket's note. It is 

 a sound similar in mechanism and char- 

 acter to that produced by running a stick 

 along a paling, and is, of course, in no 

 sense vocal, though it admits of con- 

 siderable variation in pitch. The note 

 of the male solitary but hopeful differs 

 decidedly from that of the male in prox- 

 imity to the female. He can evidently 



