Queries arid Answers, 687 



" Resounds the living surface of the ground : 

 Nor undelightful is the ceaseless hum 

 To him who muses through the woods at noon ; 

 Or drowsy shepherd, as he lies reclined, 



beneath the floating shade 



Of willows grey," Surtvnier, 



That the vibrations of innumerable wings of insects " resounds " from 

 the surface of the ground, is certainly true; but that the " ceaseless hum" 

 heard in the air proceeds from a numerous congregation of one sort of fly, 

 is equally a fact. Although I have lived by far the greater part of my life 

 in the country, it was a period of many years before I discovered the real 

 cause of this continuous hum in the air. I accustomed myself to attribute 

 it to the sound from the wings of bees, and all other insects passing and 

 repassing near the spot where I stood ; till, on one occasion, while I was 

 passing over an open eminence in a well wooded country, this hum was so 

 audible that I thought a swarm of bees was passing over-head : on looking 

 up, 1 saw no bees, but an innumerable swarm of flies disporting in the 

 sunbeams, at the height of 50 or 60 ft. from the ground. This I after- 

 wards found to be an assembly of the sexes ; not so closely thronged 

 together as to be collectively visible, but flying in very open order in all 

 directions, and in most rapid motion; requiring a keen sight to discern 

 them, either collectively or individually. Their height from the gi'ound, 

 and rapidity of flight, are the causes of their eluding the sight of those who 

 know not where to look for the source of this fairy-like sound, but a 

 strong and steady eye will readily detect the humming throng. I paid 

 attention, afterwards, to their movements, and discovered, that, after passing 

 the greater part of the day in the air, they descend to the woods, where 

 they may be both heard and seen, basking on the sunny side of the trunks 

 of trees, just before sunset. It is nearly twice the size of the common 

 house-fly, and exactly of the same form and colour. In autumn it enters 

 houses, and is often found laid up for the winter in the valance of bed and 

 window curtains. — J. M. 



The Caterpillar of the Broom Moth eats the Petals of Flowers in preference 

 to Herbage. How is it defended from the Spines of Furze, as it is devoid of a 

 hairy Covering like A'rctia Caja, the Garden Tiger? And is not the Covering 

 of the 'Qombyx Caja subservient to its Defence? — Sir, The incidental men- 

 tion, at p. 68., of the broom moth (Chesias spartiata Stephens) leads me to 

 communicate the following notice and queries respecting it : — 



In 1830, I captured a considerable number of caterpillars of this species 

 on the common furze ( t/^Mex europae^'a), when that plant was in full bloom. 

 I remarked nothing singular in their feeding at the time ; and took home 

 with me some young furze shoots, without blossoms, for them to eat. I 

 put them, with their food, into a breeding-box ; and, after some time, came 

 to see how they were going on, but not a bit had they touched. I thought 

 they might not be quite reconciled to their situation, as they seemed very 

 restless; so I left them to themselves. The next day it was the same. I 

 then sent for some fresh furze ; and they brought me some with blossoms, 

 which I placed in the box instead of the other : in a very short time they 

 had eaten every blossom, while the thorny part they had left untouched, as 

 before. 



It is well known how wonderfully the larvae of the common tiger moth 

 ( A'rctia Caja) are defended against the nettle's sting ; but those of the 

 broom moth are, to all outward appearance, entirely unprovided against 

 the dangerous thorns among which they feed. Their skin is like velvet to 

 the touch ; but, notwithstanding, I have seen them lean their whole weight 

 on the sharpest point without the least injury. Is it, then, from the elas- 



