HARDWICKE'S S C IE N CE- GO S S IP. 



237 



or oilier insects were observed. Some idea of tlie 

 ravnges committed by tliese moths may be gained 

 wlieu I say that on two elms standing close to- 

 gether, I observed, at one time, upwards of twenty 

 specimens of the perfect insect. — E. C. Lefroij, 

 Blackheatk. 



The Colours of Lepidopteea.^ read with 

 much interest the article on this subject by Mr. J. 

 Anderson (p. 175), and I was especially struck by 

 his remark on the metallic lustre which some butter- 

 flies have on their wings. He says, that no doubt 

 this is owing to scales of different shades being 

 placed transversely, like the threads in shot silks. 

 I should be very much obliged if he, or any other 

 correspondent, would say if this is correct, and if 

 not, what is the true cause of this brilliant appear- 

 .ance ?— 2?. C. Lefroy. 



How TO Clear a Pond. — I shall be much obliged 

 if any one can tell me how to get a small pond clear. 

 It is nowhere more than eighteen inches deep, the 

 water is not at all muddy, and the fish are quite 

 healthy. The thickness is solely owing to micro- 

 scopic vegetation. Can any one tell me how to get 

 rid of it ^—H. B. Rutt. 



Fecundity or the Hydra vulgaris. — The two 

 Hydras referred to in the end of my remarks on 

 them, in last June's number of Science-Gossip, 

 p. 135, as having been cut into several pieces, and 

 restored to perfect animals, when cut (on March 

 29th), I placed in a wine-glass of clean water, that 

 I might be able to watch, and observe the progress 

 they made from time to time, at the same time 

 keeping them supplied with water-fleas {Baphnea 

 Pulex), which are to be found very plentiful in 

 many ponds. The Hydra takes them very readily; 

 it is amusing to see them seize the Daphnea with 

 their tentacula and absorb them, sometimes three 

 or four at a time. The carapace or shell of the 

 Daphnea, which the Hydra rejects, together with 

 the dead bodies of those that die through coming 

 in contact with the stinging power of the Hydra, 

 sink to the bottom of the glass. To keep them 

 clean, they can easily be removed with a dipping- 

 tube, taking care not to take up any of the Hydras 

 with them. Having seen how very fast they had 

 increased by budding, after the operation of cutting, 

 on April 29th 1 removed them into a larger glass; 

 taking them out singly, and counting them, I found 

 they had, during one month, from March 29th to 

 April 29th, increased to the number of eighty-nine, 

 and most of them still had young ones growing on 

 them, some having one, others two ; so that, in all 

 probability, another week would have doubled the 

 number. In Johnston's " History of British 

 Zoophytes," p. 136, he remarks it "as most extra- 

 ordinary that polyps produced by this process grow 

 much larger, and are more prolific in the way of 

 their natural increase, than those that were never 

 cut." This I have proved. It has been said by 

 some that the Hydra can be produced perfect from 

 a single tentacle severed from the body; thisi have 

 never been able to witness, though I have tried the 

 experiment.—/. Fullagar, Canterhunj. 



Section-cutting. — Mr. Walter White's arrange- 

 ment of a section-cutting instrument with wedges 

 is very ingenious, but I think a good screw would 

 be found to answer a great deal better, besides being 

 neater^ and taking up so much less space. Perhaps 

 many of your readers may not be aware that nuts 

 and screws, beautifully cut, of various lengths and 



sizes, which are readily adapted for the purpose, 

 can be bought very cheaply at most of the London 

 tool-shops.— a T. N. 



Queen op Spain Feitillary. — Ifc may interest 

 some of your subscribers to know that a Queen of 

 Spain Fritillary {Lathonid) was caught on the 14th 

 ult., in the Warren, near Folkestone, by H. G. 

 Greenish. 



K.URAL Natural History (p. 215, 1872).— 

 Your correspondent says that in his locality some 

 of the same superstitious remedies for whooping- 

 cough are in use as in Cheshire ; but he has not 

 said where that locality is. I am collecting the 

 folk-lore of Natural History, and should be glad to 

 know where the remedies are in vogue that your 

 correspondent describes ; and shall also be grateful 

 for any further information on the subject from him 

 or any other correspondent. — Robert Holland. 



Keeping Caterpillars. — I have tried the plan 

 of keeping caterpillars mentioned by "E. T. S.," in 

 the August number, and I find it answers very 

 nicely, only I cover the top of the pot with 

 muslin tied round with string ; but I am in need of 

 help how to keep chrysalids, as some, and the 

 Privet especially, bury themselves in the mould. 

 Can any of your correspondents give me advice as 

 to how I am to manage when they are ready to 

 turn into the chrysalis state, and which is the best 

 way of keeping them through the winter ? — Mabel 

 Green, 



Swallows' Nests.— A nest built this summer 

 by a pair of swallows under the eaves of a cottage, 

 at The Maidens, Ayrshire, proved too small for the 

 family when the eggs were hatched. This the old 

 birds at once proceeded to remedy, by " building 

 an addition " at one side of the nest, and opening 

 a communication between it and the original nest ; 

 thus making what is called in Scotland. " a butt 

 and a ben." — R. G. 



The Heracleum giganteum is a native of a 

 much colder climate than ours. It grows wild, I 

 am told, in Siberia, and "J. H. G." will find, if he 

 turns to any botanical work of repute, that it 

 belongs to the genus Heracleum : our Cow Parsnip 

 is another Heracleum. This genus are all um- 

 bellifers, and " J. H. G." is perfectly correct. The 

 generic name is derived from that hero of the 

 Greek legends, Hercules. The roots and stems of 

 some of the species are eaten in various parts of 

 the world. The native tribes of North America 

 and the inhabitants of the Caucasus devour them 

 as readily as our pigs do the Cow Parsnip {Hera- 

 cleum sphondyliuiii). — H. E. W. 



Pet Starlings, &c. — In answer to " G. T. J." 

 in last month's number of Science-Gossip, I beg 

 to inform him that by using a hollow perch made by 

 pushing out the pith of a small elder-stick, and 

 cutting into the tube, so to make a number of notches 

 or holes, the parasites will be found in this hollow 

 perch, by taking it out of the cage and tapping it, 

 whilst holding it upright, into a glass of water.— 

 R. Allison. 



Where are the Swallows ?— With the excep- 

 tion of a few sultry days we have had little weather 

 such as the swallows delight in, which probably 

 accounts for their scarcity. There are not more than 

 half as many swallows, &c., in Devon as there was 

 last year, and they came very IdXt— Arthur Smyth. 



