i 7 8 



SCIENTIFIC NEWS. 



[Aug 24, 1888. 



inch thick, and below it is a second piece of the same 

 length, but just 2 inches wide. The second piece enters 

 the slot in the sliding strip, a, and the slide carrier rests 

 upon the shoulders formed by the upper block. A hand 

 screw, d, is arranged to hold the slide carrier in any 

 desired position. 



A smaller movable mirror, D, is supplied to be sup- 

 ported above the objective when the lantern is to be 

 used for vertical projection. 



A piece of sheet iron is fastened across the bottom of 

 the main frame, on which the lantern, E, rests. In the 

 front of the same frame a notch is cut in which the 

 piece, A, rests. TVmake its position in the front con- 

 denser board more secure, a second strip may be attached 

 just below the mortise and to the back of the board. 



For lantern any good form of screened lamp may be 

 used. If necessary, .a sheet-iron box may be arranged 

 to inclose the source of light; but with such a lantern 

 as is here shown it is quite unnecessary. 



In the drawings, Fig. 1 shows the whole ready for 

 mounting, the lamp being lighted and ready for work. 

 The lamp should always be lighted before beginning, as 

 it may take five minutes for it to attain its full power. 

 Fig. 2 shows the whole put together and arranged for 

 exhibiting views. By removing the slide carrier the 

 entire space between condenser and objective is free for 

 the introduction of apparatus or performance of experi- 

 ments. A soap bubble can be blown and projected in 

 this space. A glass of water can be very prettily 

 shown, and the lantern will be found admirably adapted 

 for the experimenter's use. Fig. 3 shows the lantern 

 arranged for vertical projection, the outline of the mirror 

 being given in dotted lines. As the slide carrier is not 

 always used for work in this position, it, too, is shown 

 in dotted lines. 



If all is properly constructed, the apparatus will be 

 susceptible of all kinds of adjustments. The sliding 

 board, a, can be moved back and forth in the mortise in 

 the front condenser board. The slide carrier can also 

 be moved backward and forward. By these two adjust- 

 ments the slide carrier can be brought to any point 

 desired in the cone of rays converging from the con- 

 densers. By moving the lantern backward and forward, 

 any modification in the direction of the light rays emerg- 

 ing from the condenser can be given. 



A lime-light can be used instead of an oil lamp ; but 

 as the object was to show a portable lantern, the former 

 has been shown in the cuts. — Scientific American. 



NOTES FOR YOUNG COLLECTORS. 



'T'HEfollowingnotes, theresultoflongexperience abroad, 

 -»- may not all be available for entomologists in Britain. 

 But in view of the increasing facility and cheapness of 

 travelling and the frequency of emigration, it may be 

 hoped that more and more of our rising entomologists 

 will no longer confine themselves to British insects, but 

 go out to wider and less threadbare fields. In no other 

 part of the world is so much annoyance sustained from 

 the trespass laws and from the interference of game- 

 keepers. In other countries, so long as you do not 

 encroach upon lands under actual cultivation, you need 

 fear no interference. 



Perhaps the first caution to be observed by the young 

 collector is to avoid the interior of forests, as compara- 

 tively barren. Their margins, whether bordering on 



arable land, pastures, heaths, or pieces of water, are very 

 generally found fruitful. Lanes or avenues cut through 

 a dense forest often yield a rich harvest. So do openings 

 of a few score yards in width, screened from the wind on 

 all sides, especially if they include a pool or a patch of 

 marshy ground. One of the best of all localities is a 

 clearing where the trees have just been removed and 

 the stumps are still standing. 



A great variety of lepidoptera, and not a few 

 beetles, especially the splendid Buprestida, come to feast 

 on the sap oozing out of the wood. 



Chalk, sand, and gravel pits, especially if they have been 

 left undisturbed for some time, are always worth a care- 

 ful examination. The margins of foot-paths leading 

 across pastures and meadows and through corn-fields 

 are ofcen rich in Elateridce, especially species of Gtenicera. 



Stony and shingly districts are often rich in ground- 

 beetles, Carabs, Harpalida, etc., which may be found by 

 cautiously turning the stones over. This applies, how- 

 ever, only in localities where stones are naturally preva- 

 lent. A casual heap of stones in other localities rarely 

 yields anything worth picking up. 



Rivers in time of flood are often very prolific. If the 

 collector provides himself with a small water-net with a 

 long handle, and takes his stand at some point where the 

 current is obstructed — e.g., by the piers of bridges, jetties, 

 etc. — he may sometimes scoop up beetles by the pint, 

 Geodophaga of almost every description occurring in the 

 neighbourhood, Necrophaga, Geotrupidce, and many others. 

 The best way is to bring away the whole lot, and sort 

 them at home. Those not wanted should be set at 

 liberty, as by far the greater number of those likely to 

 be thus captured are harmless, if not actually beneficial. 

 You will find that Carabs, to all appearance drowned, will, 

 if laid in a sunny spot, gradually revive and run away. 



Certain localities are to be avoided as not likely to be 

 worth the time spent upon them. Such are districts 

 swarming with ants, whether they be woodland, heath, or 

 desert. Here the larvae, the pupae, and all adult insects 

 haunting the ground and the lower trees (with the excep- 

 tion of certain species which seem to live on friendly 

 terms with the ants) will have ~been devoured. Grass- 

 lands which are mown repeatedly during the course of 

 the summer — as it is often done in Switzerland — are of 

 little use, since many species of plants are thus extirpated, 

 and the insects which feed upon them are banished. The 

 neighbourhood of a flourishing rookery is seldom rich in 

 insects ; these birds are very diligent and successful in 

 digging up and devouring buried larva? and pupa;, and in 

 ransacking small carrion, dung, etc., for a variety of insects. 



Where moles abound the prospects of the collector, at 

 least as far as certain groups of insects are concerned, are 

 not very bright. Land which has been heavily dressed 

 with chemical manures is often shunned by insects, 

 whilst, on the contrary, many kinds flock where farm-yard 

 manure, night soil, crushed bones, etc., have been applied. 



Plank-fences and the sides and tops of sheds and out- 

 houses which have been recently coated either with gas- 

 tar or wood-tar may be let alone by the collector, for 

 they will assuredly be boycotted by insects. 



Very much depends upon the kind of weather. Pro- 

 longed drought and prolonged wet are equally objection- 

 able to our creeping and flying friends. They prefer a 

 mixture of sunshine and showers, with as little wind as 

 possible. In tropical climates the beginning and the end 

 of the rainy season, and especially any intervals of fine 

 weather which intervene, are good times for collecting. 



