480 MOTIONS OF INSECTS. 



like the claws of a lobster, but sharper, in heaths ancf other dry situations 

 it pel forates and rounds its curious and regular cells. The house-cricket 

 (G.domesticus), which, on account of the softness of the mortar, delights, 

 in new-built houses, with the same organs, to make herself a covered-way 

 from room to room, burrows and mines between the joints of the bricks 

 and stones. 1 



But of all the burrowing tribes, none are so numerous as those of the 

 order Hymenoptera. Wherever you see a bare bank, of a sunny exposure, 

 you usually find it full of the habitations of these insects ; and almost 

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

 them. Bees, wasps, bee- wasps (Bembex), spider-wasps (Pompilus), fly- 

 wasps (Mellinus, Cerceris, Crabro\ with many others, excavate subter- 

 ranean or ligneous habitations for their young. None is more remarkable 

 in this respect than the sand-wasp (Ammophila). 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. 8 



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 (Tipula 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 ovipo- 

 sitor, which terminates her long cylindrical pointed abdomen, made its 

 way into the hard soil, and deposited her eggs in a secure situation. 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 sus- 

 pended by one of his legs on a twig, not far from her. The common turf- 

 boring crane-fly (T. oleracea), when engaged in laying eggs, moves over 

 the grass with her body in a vertical position, by the help her four an- 

 terior 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 Reau- 

 mur's account. 3 



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. 4 I have frequently amused myself with 

 watching them ; but when I have endeavoured 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 them- 



1 White, Nat. Hist. ii. 72. 76. 80. 



2 Linn. Trans, iv. 200. See Westw. in Trans. Ent. Soc. vol. i. p. 198. on the coa 

 Btruction of the burrows of this and some allied species. 



& v. 20. 4 vL 10-i. 



