286 Qiieries and Ans'uoers. 



tap it a few hours after, if the day be moderately warm, and the juice will issue 

 in streams. February, and early in March, are the months in which the sugar 

 is made. The people encamp in the woods, and remain there until the trees 

 cease to flow, or they have procured as much as they require. Now, 1 wish 

 to know, if the saccharine juice be sap, how it happens that a moderately cold 

 night is essential to an abundant flow next day ? _ The farmers told me, " We 

 can do nothing in sugar-making without cold nights." I thought that the 

 sap never flowed until an increase of temperature took place ? — J. M. Phila- 

 dehpUa, March 16. 1837. 



Why are Chaffinches deterred hy a Line of hlach Thread, ivhen they do not 

 dread a Thread luith Bits of Rag attached to it? It has struck me that this 

 curious fact, mentioned by Mr. Anderson (p. 172.), is quite analogous to the 

 circumstances stated by Mr. Spence in the Transactions of the Entomological 

 Society (described in the Architectural Magazine, vol. ii. p. 188., and quoted 

 below), that flies will not pass through a net with the meshes 1 in. wide, by 

 which means rooms may be kept quite clear from them by hanging a net of 

 this kind in front of the window. To what is the existence of dread in both 

 cases attributable ? — J. 0. 7'F. May \7. 1837. 



" The Italian Mode of excluding the Common House Fly (Jfliusca domestica L.) 

 fro7n Apartments. — This mode was pointed out to William Spence, Esq., in 

 Italy, two or three years ago, and is published in the first number of the Trans, 

 of the Eiitomological Society ; and his son has subsequently discovered that it 

 was known in the time of Herodotus, and practised by the fishermen of 

 Egypt. It is simply to cover the openings of the windows by a net of white 

 or light-coloured thread. It is remarkable that the meshes of this net may 

 be an inch or more in diameter, so that there is actually no physical obstacle 

 presented to the entrance of the flies even with expanded wings. The flies 

 seem to be deterred from entering from some inexplicable dread of venturing 

 within the network. It is even found that, ' if small nails be fixed all round 

 the window frame, at the distance of about an inch from each other, and 

 threads be then stretched across both vertical^ and horizontally, the apparatus 

 will be equally effectual in excluding the flies.' It is essential, however, that 

 'the light should enter the room on one side of it onlyj for if there be a 

 thorough light, either from an opposite or side window, the flies pass through 

 the net without scruple.' (Trans. Ent. Soc, i. 4.) 



"The above facts are of interest both to the occupiers of houses and shops 

 in temperate climates, and the architects of houses for warm countries. They 

 also supply useful hints to butchers, and, indeed, to all persons to whom flies 

 and gnats are an annoyance. The facts further show, that sciences apparently 

 the most remote from architecture may yet afford useful hints for improving 

 that art. To gardeners these facts afford excellent hints for excluding flies 

 from vineries and peach-houses, and from ripe grapes and other fruit against 

 walls. — Cond." 



Otiorhynclms sidcdtus. — It appears that this destructive insect, of whose 

 habits, as injurious to collections of succulent plants, an account is given by 

 Mr. Westwood in p. 158., is not confined to that tribe of plants, but is occa- 

 sionally injurious to wall fruit and vines, as appears from the following 

 communications, which were accompanied by specimiens of the weevils in 

 question : — 



" These insects are from the peach-house at Hampton Court. They eat 

 holes in the fruit, and eat the leaves to a great extent ; so much so, that the 

 gardeners are obliged to get up in the nighttime and catch them. In the day- 

 time the insects go into crevices in the wall." — J. Castles. Botanic Garden, 

 Twickenham, May 12. 1837. 



" An insect greatly resembling that described, and figured in p. 158.*, was 



* The specimens sent with this communication were specifically identical 

 with the weevils raised from succulent plants, as described in the page referred 

 to, and those received from Hampton Court.- — J. O. W, May 17. 1837. 



