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HARDWICKE'S SCIENCE-GOSSIP. 



The English House-fly in New Zealand.— 

 One lar^e blue- bottle fly is a terrible torment in 

 New Zealand. Not only does he "fly-blow" the 

 meat, but he lays his eggs in the blankets also, 

 with the usual unpleasant results, if tbey are not 

 at once got rid of. But the house-fly was, until 

 lately, unknown. The folio -.vhig history was told 

 to me by a friend lately returned from Christ- 

 church, New Zealand, where he had worked for the 

 last six years. A few years ago it occurred to a 

 resident in New Zealand that if the common house- 

 fly could be introduced from England it would 

 assist in exterminating the blue-bottle. Accord- 

 ingly, when the time came for him to take a holiday 

 to the old country, he did not forget to collect flies 

 just before his return. He kept them in a box 

 during the voyage, and fed them with bread and bits 

 of sugar, and not many lives were lost. The party 

 arrived at an accommodation-house on the Hakaia 

 river, and here the caution of our naturalist appears 

 to have deserted him. He opened his box either 

 to feed or display his flies, and through some inad- 

 vertence the whole of them escaped. But the 

 experiment was not without some results. My 

 friend and informant came to England a few months 

 ago, and he says that the common house-fly is 

 thoroughly domesticated in New Zealand, but with 

 what result with regard to the blue-bottles he is 

 unable to state, more than that where the flies are 

 numerous the blue-bottles are certainly scarce. 

 Does this account of the introduction of house- 

 flies appear true? I relate it as it was told to me, 

 but it:.seems to me unlikely that the flies would 

 have lived through the voyage. Have any of your 

 correspondents heard the flies accounted for before, 

 or this story in any other form ? — M. A. D. 



^The Ermine in North Wales.— What does 

 "W. P." in last month's Science-Gossip mean 

 by saying that the Ermine is rare in North Wales, 

 but the" Stoat, Weasel, &c., are common enough " ? 

 Of course he is not ignorant of the fact that the 

 Ermine {Mustela Erminea) is simply the Stoat in 

 its winter coat. I have lately seen a specimen 

 of the Erminea which was killed before it had 

 completed its transformation; the lower half of 

 its body is white and the upper brown. I should 

 like to know the meaning of " W. P.'s " communi- 

 cation, as it would be a curious fact if most of 

 the stoats die before assuming their winter dress. — 

 W. W. 



Variety of the Tufted Duck.— I should be 

 glad if " P. P." would kindly favour us with a 

 more minute description, of the plumage of the 

 duck he mentions in the February number, also 

 the colour of the iris, the legs and feet, when 

 fresh, and the extent of the bulf colour upon the 

 lower part of the breast. Does it blend with the 

 dark colour of the lower neck, or is the band 

 across the chest well defined, and of the usual 

 colour? I should also like to know if any of the 

 buff colour extends to the sides and vent-feathers. 

 —~T. Southwell. 



Why do Caterpillars weave Webs? — The 



author of a paper in last month's issue of Science- 

 Gossip, on the "Web- weaving Caterpillars," invites 

 observers to offer their opinions on tiie reasons why 

 some lepidopterous larvaj are endued with this 

 habit, it is not easy to give a satisfactory answer 

 which will meet all cases. One thing would strike 

 us as notable at the outset ; namely, tliat a very 

 Jarge number — the majority in fact— of those which 



spin webs or form nests are hairy caterpillars, and 

 therefore, as a consequence, the less in need of 

 any protection of their own making to screen them 

 from birds ; for I presume, in the caterpillar-hunt- 

 ing species, it will be found, as a rule, that they 

 prefer smooth-skinned to hairy individuals when 

 they can get them. And again, it must be remem- 

 bered that many solitary larvae which do not form 

 a web for their protection are in the habit of 

 employing their silken store occasionally in spinning 

 a web, or else some slight shelter for themselves in 

 windy weather,_or during the periods when they 

 are casting their skins. Among the uses which 

 caterpillars' webs^ subserve, these may be indi- 

 cated :— 1. They aflord the caterpillars a screen from 

 rain, high wind, and moderate also the influences 

 produced by changes of temperature. 2. They 

 protect them during their changes of skin. 3. 

 They may insure the caterpillars a firm foothold 

 while feeding, often a circumstance of importance. 

 Some species are most cai'cful to extend their 

 webs or nests so as to cover the different boughs 

 or twigs upon which they feed. 4. They ward off 

 the attacks of birds, at least sometimes, and may 

 also prove a safeguard against parasitic insect 

 enemies. As to the Lackey {B. Keustria), which 

 Mr. Lovekin has referred to amongst others, 

 it is observable that when the caterpillar becomes 

 of good size its social habits cease, and each 

 wanders separately. 1 was certainly not aware, 

 however, that this caterpillar is more fortunate 

 than its brethren in being nearly exempt from the 

 peril of being devoured by birds. The Gold-tail 

 {L. aitriflua), though conspicuous enough in the 

 early summer, does not then conceal itself by a 

 web, which, in this species, is only formed as a 

 winter retreat. — /. R. S. C. 



Large Green Grasshopper. — I found that 

 this insect would readily eat raw beef some years 

 ago, and I then noticed the fact in Science-Gossip. 

 1 have since tried some experiments with another 

 specimen, and found it was very partial to apple- 

 leaves and small grasshoppers; but the uncooked 

 meat offered him was refused; so I came to the 

 conclusion that grasshoppers, like human beings, 

 differ in their taste respecting diet. — Hele/i E. 

 Watney. 



Singing Mice.— I cannot give the same experi- 

 ence of singing mice as your correspondent last 

 month. The singing mice in my present residence, 

 on the banks of the Khine, sing while running in 

 the room, and only seem to intermit while feeding, 

 and but for a moment. The sound varies from a 

 soft cheep-chirp to that of a spring running down 

 when over-wound, but more regular, and gives 

 the idea of activity and glee. These mice, both 

 singing and mute, are much larger than English 

 house mice, and often dig large holes in the earth 

 round my plants in pots. They also eat the leaves 

 of some plants, so as to strip them, and only yester- 

 day bit off the tops of a bouquet of violets 

 (Neapolitan), primulas, &c. On several occasions 

 they have attacked my canaries, which I suppose 

 to be unusual. Can your other correspondents in- 

 form me if they have experienced the like? All 

 the mice frequenting my house are singularly bold, 

 and comparatively indifferent to noise, continuing 

 their employments while the iron of my stove 

 rattles I'rom their efforts. Cheese is held of no avail 

 here in trapping mice; they can only be tempted by 

 meat. — Tedesca, Prussia. 



