476 



HISTORY OF INSECTS. 



not this power, but either walked or "flew. 1 

 The little hissing note also of our grasshopper 

 is very different from the song of the cicada, 

 which was louder and far more musical. The 



> The Cicada is celebrated for its song, by the ancient 

 Greek poets, under the name of TSTT;|. The Romans 

 called it Cicada, which we sometimes, but erroneously, 

 translate " grasshopper ;" for the grasshoppers belong to 

 an entirely different order of insects. We shall, there- 

 fore, (says Mr Rennie) take the liberty of calling the 

 Cicadse, Tree-hoppers, to which the cuckoo-spit insect 

 (Tettigonia spumaria, Oliv.) is allied; but there is only 

 one of the true cicadte hitherto ascertained to be British, 

 namely, the Cicada hamatodes (Linn.) which was taken 

 iu the New Forest, Hampshire, by Mr Daniel Bydder. 

 M. Reaumur was exceedingly anxious to study the 

 economy of those insects; but they not being indigenous 

 in the neighbourhood of Paris, he commissioned his friends 

 to send him some from more southern latitudes, and he 

 procured in this way specimens not only from the South 

 of France and from Italy, but also from Egypt. From 

 these specimens he has given the best account of them 

 yet published ; for though, as he tells us, he had never had 

 the pleasure of seeing one of them alive, the more inter- 

 esting parts of their structure can be studied as well in 

 dead as in living specimens. We ourselves possess se- 

 veral specimens from New Holland, upon which we have 

 verified some of the more interesting observations of 

 Reaumur. 



Virgil tells us, that in his time " the cicadse burst the 

 very shrubs with their querulous music;" but we may 

 well suppose that he was altogether unacquainted with the 

 singular instrument by means of which they can actually 

 (not poetically) cut grooves in the branches they select 

 for depositing their eggs. It is the male, as in the case 

 of birds, which fills the woods with his song; while the 

 female, though mute, is no less interesting to the natu- 

 ralist on account of her curious ovipositor. This instru- 

 ment, like all those with which insects are furnished by 

 nature for cutting, notching, or piercing, is composed of 

 a horny substance, and is also considerably larger than 

 the size of the tree-hopper would proportionally indicate. 

 It can on this account be partially examined without a 

 microscope, being, in some of the larger species, no less 

 than five lines * in length. 



The ovipositor or auger (tariere) as Reaumur calls it, 

 is lodged in a sheath which lies in a groove of the termi- 

 nating ring of the belly. It requires only a very slight 

 pressure to cause the instrument to protrude from its 

 sheath, when it appears to the naked eye to be of an equal 

 thickness throughout except at the point, where it is 

 somewhat enlarged and angular, and on both sides finely 

 indented with teeth. A more minute examination of 

 the sheath demonstrates that it is composed of two horny 

 pieces slightly curved, and ending in the form of an elon- 

 gated spoon, the concave part of which is adapted to re- 

 ceive the convex end of the ovipositor. 



When the protruded instrument is further examined 

 with a microscope, the denticulations, nine in number on 

 each side, appear strong, and arranged with great sym- 

 metry, increasing in fineness towards the point, where 

 there are three or four very small ones, beside the nine 

 that are more obvious. The magnifier also shows that 

 the instrument itself, which appeared simple to the na- 

 ked eye, is in fact composed of three different pieces, tw 

 exterior armed with the teeth before-mentioned, deno- 

 minated by Reaumur files, (limes), and another pointed 

 like a lancet, and not denticulated. The denticulated 

 pieces moreover are capable of being moved forwards and 

 backwards, while the centre one remains stationary, and 

 as this motion is effected by pressing a pin or the blade 

 of a knife over the muscles on either side at the crigii 

 * A line is about the twelfth part of an inch. 



manner in which this note is produced by the 

 two animals is very different ; for the cicada 

 makes it by a kind of buckler, which the male 

 bas beneath its belly ; the grasshopper by a 



of the ovipositor, it may be presumed that those muscles 

 are destined for producing similar movements when the 

 insect requires them. By means of a finely pointed pin 

 carefully introduced between the pieces, and pushed very 

 gently downwards, they may be, with no great difficulty, 

 separated in their whole extent. 



The contrivance by which those three pieces are held 

 united, while at the same time the two files can be easily 

 put in motion, are similar to some of our own mechani- 

 cal inventions, with this difference, that no human work- 

 man could construct an instrument of this description so 

 small, fine, exquisitely polished, and fitting so exactly. 

 We should have been apt to form the grooves in the cen- 

 tral piece, whereas they are scooped out in the handles of 

 the files, and play upon two projecting ridges in the cen- 

 tral piece, by which means this is rendered stronger. M. 

 Reaumur discovered that the best manner of showing the 

 play of this extraordinary instrument is to cut it off with 

 a pair of scissors near its origin, and then, taking it be- 

 tween the thumb and the finger at the point of section, 

 ivork it gently to put the files in motion. 



Beside the muscles necessary for the movement of the 

 files, the handle of each is terminated by a curve of the 

 same hard horny substance as itself, which riot only fur- 

 nishes the muscles with a sort of lever, but serves to 

 press, as with a spring, the two files close to the central 

 piece, as is shown in the lower figure. 



M. Pontedera, who studied the economy of the tree- 

 hoppers with some care, was anxious to see the insect it- 

 self make use of the ovipositor in forming grooves in 

 wood, but found that it was so shy and easily alarmed, 

 that it took to flight whenever he approached; a circum- 

 stance of which Reaumur takes advantage to soothe his 

 regret that the insects were not indigenous in his neigh- 

 bourhood. But of their workmanship when completed, 

 he had several specimens sent to him from Provence and 

 Languedoc by the Marquis tie Caumont. 



The gall-flies, when about to deposit their egg=, se- 

 lect growing plants and trees ; but the tree-hoppers, on 

 the contrary, make choice of dead, dried branches, for 

 the mother seems to be aware that moisture would injure 

 her progeny. The branch, commonly a small one, in 

 which eggs have been deposited, may be recognised by 

 being covered with little oblong elevations caused by 

 small splinters of the wood, detached at one end, but left 

 fixed at the other by the insect. These elevations are 

 for the most part in a line, rarely in a double line, nearly 

 at equal distances from each other, and form a lid to a 

 cavity in the wood about four lines in length, containing 

 from four to ten eggs. It is to be remarked, that the in- 

 sect always selects a branch of such dimensions, that it 

 can get at the pith, not because the pith is more easily 

 bored, for it does not penetrate into it at all, but to form 

 a warm and safe bed for the egg?. M. Pontedera says, 

 that when the eggs have been deposited, the insect closes 

 the mouth of the hole with a gum capable of protecting 

 them from the weather; but M. Reaumur thinks this 

 only a fancy, as out of a great number which he exam- 

 ined, he could discover nothing of the kind. Neither is 

 such a protection wanted; for the woody splinters above 

 mentioned furnish a very good covering. 



The grubs hatched from these eggs (of which, M. Pon- 

 tedera says, one female will deposit from five to seven 

 hundred) issue from the same holes through which the 

 eggs have been introduced, and betake themselves to the 

 ground to feed on the roots of plants. They are not 

 transformed into chrysalides, but into active nymphs, re- 

 markable for their fore limbs, which are thick, strong, 

 and furnished with prongs for digging- and when we are 



