MOTIONS OF INSECTS. 363 



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 a . 



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 always find it full 

 of the habitations of insects belonging to it; and besides 

 this, 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 (Melli- 

 nus, Cerceris, Crabro), with many others, excavate sub- 

 terranean or ligneous habitations for their young. None 

 is more remarkable in this respect than the sand-wasp 

 (Ammophila), or as it might be better named since 

 it always commits its eggs to caterpillars which it in- 

 humes the caterpillar-wasp. It digs its burrows, by 

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

 spersing with its hind ones, which are particularly con- 

 structed for that purpose, the sand so collected 5 . 



Since most of these burrows are designed for the re- 

 ception of the eggs of the burrowers, I shall next de- 

 scribe 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 stretch- 

 ed out on each side, and kept turning herself half round 

 backwards and forwards alternately. Thus the oviposi- 

 tor, which terminates her long cylindrical pointed abdo- 

 men, made its way into the hard soil, and deposited her 



H White, Nat. Hist. ii. 80. 72. 76. , b Linn. Trans, iv. 200. 



