MOTIONS OF INSECTS. 515 



almost every rail and old piece of timber is with the same view perforated 

 by them. Bees, wasps, bee-wasps (Bemhex), spider-wasps (Pompilus), 

 fly-wasps (^Mellinus, Cerceris, Crahro), with many others, excavate sub- 

 terranean or ligneous habitations for their young. None is more remarka- 

 ble in this respect than the sand-wasp {Ammophild). It digs its burrows, 

 by scratching with its fore-legs like a dog or a rabbit, dispersing with its 

 hind ones, which are particularly constructed for that purpose, the sand so 

 collected.^ 



Since most of these burrows are designed for the reception of the eggs 

 of the burrowers, I shall next describe to you the manner in which one of 

 the long-legged gnats, or crane-flies (Tiyula variegata) — a proceeding to 

 which I was myself a witness — oviposits. Choosing a south bank bare 

 of grass, she stood with her legs stretched out on each side, and kept 

 turning herself half round backwards and forwards alternately. Thus 

 the ovipositor, which terminates her long cylindrical pointed abdomen, 

 made its way into the hard soil, and deposited her eggs in a secure situa- 

 tion. All, however, were not committed to the same burrow ; for she 

 every now and then shifted her station, but not more than an inch from 

 where she bored last. While she was thus engaged, I observed her male 

 companion suspended by one of his legs on a twig, not far from her. The 

 common turf-boring crane-fly (T. oleracca), when engaged in laying eggs, 

 moves over the grass with her body in a vertical position, by the help — 

 her four anterior legs being in the air — of her two posterior ones, and the 

 end of her abdomen, which performs the office of another. Whether in 

 boring, like T. variegata, she turns half round and back, does not appear 

 from Reaumur's account.^ 



I now come to motions whose object seems to be sport and amusement 

 rather than locomotion. They may be considered as of three kinds — 

 hovering — gyrations — and dancing. 



You have often in the woods and other places seen flies suspended as it 

 were in the air, their wings all the while moving so rapidly as to be almost 

 invisible. This hovering, which seems peculiar to the aphidivorous flies, 

 has been also noticed by De Geer."^ I have frequently amused myself 

 with watching them ; but w^ien I have endeavored to entrap them with 

 my forceps, they have immediately shifted their quarters, and resumed 

 their amusement elsewhere. That their object is simply amusement seems 

 proved by the fact noticed by Mr. Curtis, that " if you catch a dozen in 

 your morning's walk, they are all males who are thus enjoying themselves."^ 

 The most remarkable insects in this respect are the sphinxes, and from 

 this they doubtless took their name of hawTc-moths. When they unfold 

 their long tongue, and wipe its sweets from any nectariferous flower, they 

 always keep upon the wing, suspending themselves over it till they have 

 exhausted them, when they fly away to another. The species called by 

 collectors the humming-bird (^Macroglossa stellatarum), and by some per- 

 sons mistaken for a real one, is remarkable for this, and the motion of its 

 wings is inconceivably rapid.^ 



The gyrations of insects take place either when they are reposing, or 



> Linn. Trans, iv. 200. See Westw. in Trans. Ent. Soc. vol. i. p. 198. on Ihe construction 

 of the burrows of this and some allied species. 



* V. 20. 3 vi. 104. * Gardener's Chronicle, 1841, p. 52. 



* Rai. Hist. Ins. 133. 1. 



