Nov. 24, 1882.] 



KNOWLEDGE • 



421 



2 to 1 between the densities, where the lines of vision 

 touch the moon's edge. Bnt except in occultations of stars 

 ■we cannot really use such tangent visual lines, though we 

 may seem to do so. — Ed.] 



BUTTERFLIES AND MOTHS. 



Bv W. J. II. Clark. 



THERE are many other methods employed in pupa 

 hunting besides digging, and at this period of the 

 year, all will prove more or less productive, and though a 

 very large proportion of the captures will probably consist 

 of very common species, yet now and then a rarity will be 

 obtained which will amply repay all the trouble which may 

 have been taken with the others. 



Among the best localities for pupa hunting, besides 

 those noticed in last paper, we may mention woods where 

 clearings have been made, open heaths and commons, 

 coasts, sand-hills, fields, &c. 



An open light soil will be the most productive, while 

 hard, wet clay will yield nothing for our pains. Dead 

 foliage lying on the ground will also give good results if 

 very carefully examined and raked over, but it must be 

 well shaken about for any pup.i' which might liave attached 

 themselves to the leaves. The best way is to take a large 

 sack and fill it v/ith leaves, and, after having brought it 

 home, to subject them to a thorough examination at 

 leisure. 



Next, the leaves of trees must be examined for the pupa? 

 of those moths which spin the leaves together when under- 

 going their change from the larval to the pupal state. 

 When a leaf is found rolled up, it may be nearly always 

 suspected to contain a pupa of some kind or other, and 

 should not be unfolded, but brought home intact on spec. 

 However, if we wish to make perfectly sure as to whetlier 

 there is any inhabitant or not, hold it up to the light, 

 when the outline of the contained pupa will be clearly seen 

 through the semi-transparent leaf. A large number of 

 the Tortrices and various others will be obtained in this 

 way. 



In the cracks and other irregularities on the bark of 

 trees will often be found the chrysalides of several of the 

 Bomhiiccs and others, and the tree should be thoroughly 

 searched all round. If anything be found, do not attempt 

 to detach it by force, but cut away the piece of bark or 

 wood to which it is joined as well. If there be any pieces 

 of loose bark on the tree, endeavour to tear them ofl', as 

 very often large numbers of pupa? will be found sheltering 

 underneath. 



Some larva) burrow right into the wood itself, and for 

 these a very particular search must be made, as their 

 haunts are not so easily found out. We have all seen the 

 large tunnels made by the Goat moth {Coskus I'ujniperda) 

 in our apple-trees, and other smaller tunnels constructed 

 by various Si'siada', &c., and the question is how to get at 

 the inhabitants. The best way is to cut oil' the branch or 

 branches and take them home, and there wait patiently 

 until the imago emerges. 



All small bushes should be carefully examined, both on 

 the branches and among the leaves ; the roots, itc, should 

 also be looked over, as several species of larva- go amidst 

 the network of shoots for a resting-place. 



The grass and other low plants should be thoroughly 

 searched, and all rubbish of any kind turned over and 

 examined ; .sheltered walls, underneath tlie ledges of walls 

 and outbuildings, old fences, Ac, will also yield good 



results ; in fact, there is no outdoor situation which does 

 not often form a home for some larva or other. 



The pupie of I/i/droctuiijtir/n' and other water-inhabiting 

 species can only be obtained 1 ly dragging among the aquatic 

 plants with a small meshed water-net. 



When we have obtained our pupas, the great thing is to 

 keep them so that as large a number as possible may 

 develope into the perfect insect. This requires careful 

 treatment, which, for different species, must be of different 

 natures. 



In all cases the source from which the pupa was 

 obtained must guide us in keeping it, and we should 

 always endeavour to follow nature as nearly as possible if 

 we wish to succeed in anything connected with the rearing 

 of either larv;e or pupie. 



Pupa^ which have been obtained from under the surface of 

 the earth must be treated as follows : — They should be kept 

 in an earthenware pan containing some light, friable soil, 

 which is not too dry, and a layer of moss put on top, which 

 must occasionally be sprinkled with water in order to keep 

 up the moisture of the soil ; be very careful not to make the 

 soil ivet, but only naturally moist, as if it be kept too 

 damp, most of the pupa' will be lost from mould, or will 

 rot away. 



For those chrysalides which have been obtained from 

 twigs or walls and places exposed to the air, we must make 

 a frame consisting of four pieces of wood joined together 

 at right angles thus Q, with a piece of muslin or gauze 

 stretched over them, so as to form a sort of tray, on which 

 the pupa; are to be laid, and hung up in an outhouse, or 

 where a current of fresh air is continually passing, as this 

 prevents the ravages of disease and mould. 



The pup;e captured by water-dragging must be kept in 

 jars or globes, filled with water, and covered over with 

 muslin or gauze. 



Some one of the above-mentioned methods of rearing w-ill 

 do for nearly every species which can be found in this 

 country, but exotic and other foreign pupie require special 

 treatment, varying according to the climate and surround- 

 ings of the country in which they are found. 



Substance for Casts. — A prize of £500 was oflered in 

 1877 by the German Government for the invention of a 

 material as suitable as gypsum for taking casts of works 

 of art, and yet capable of repeated cleaning. Forty-one 

 candidates have sent in specimen casts, but none have been 

 judged so absolutely satisfactory as to gain the prize. — 

 Mechnincnl Work/. 



Is Lowell, Mass., there is a telephone for every 62 in- 

 habitants, although the population numbers some 20,000 

 mill-hands. In PortLand, Maine, there is a telephone for 

 every 50 inhabitants. The telephones do as much busi- 

 ness as the telegraph lines between those cities, and yet the 

 telegraph company does 50 per cent more business than it 

 did two years ago. 



Wire FENCiN<i in Thuxderstorms. — During a tliunder- 

 storm recently, fi\e sheep were killed on the farm of Goth- 

 land, Tinwalcl parish, in Scotland. In one field there was 

 a wire fence for a distance of 300 yards. The current had 

 travelled along this, breaking the wooden posts at various 

 distances, and at the end of the fence two sheep were 

 struck and killed. In an adjoining field, separated from 

 the other by a farm road, the fence was a stone wall, with 

 a single wire on the top. This wire was broken, and 

 touched the ground about forty yards from the road. A 

 number of slieep were crouching near the broken wire, 

 and three of them were killed. 



