ZOOLOGY AND BOTANY, MICEOSCOPY, ETC. 731 



operating on, lightly upon tlie Canada balsam film in tlie position you 

 desire. If a dorsal view is required, and a winged insect tlie sub- 

 ject, place it back upwards, then with a fine needle or pin arrange its 

 legs and wings. The legs may be made to adhere their entire length 

 to the balsam, but it is desirable that only the tips of the wings be 

 held down by the balsam. In this position the insect should remain 

 for two or three hours to allow the balsam to become harder and the 

 limbs of the insect stiffer. Then place the piece of glass with the 

 insect adhering to it in spirits of wine, where it should be allowed to 

 remain for two or three days. It is not unlikely that in the course 

 of a few hours the action of the spirits may cause the film of balsam 

 to become detached from the glass. This will not matter, for the har- 

 dened film will be found sufficiently dense and strong to keep the legs 

 and wings of the insect in the position they were originally placed in 

 by the setting needle. Should, however, the film not become detached 

 when it is time to withdraw the piece of glass from the spirits, it is 

 easy to remove the insect by placing the piece of glass in spirits of 

 turpentine, which will dissolve the hardened balsam. If, as mentioned 

 before, the film has become detached from the glass, a few hours after 

 its first immersion in the spirits, it should remain undisturbed in the 

 spirits for some days, and then it can be treated with turpentine. It 

 should be kept in clear spirits of turpentine until it has become suffi- 

 ciently transparent for mounting in Canada balsam. 



There are some species of spiders that will crumple up their legs 

 unless pinned out. The pinning out is not at all a difficult process ; 

 it merely takes a little more time. Fasten with fine tin wire a thin 

 cutting of cork to a piece of glass, then spread a thin film of Canada 

 balsam on the cork. Lay the spider in position on the balsam, and 

 having previously cut the points of a number of fine pins, take the points 

 up with a pair of light forceps and stick them into the cork against the 

 inner side of the legs of the spider. One point, if properly placed, will 

 be sufficient for each leg. The palpi and mandibles may also be kept 

 in position in the same way. After this has been accomplished put the 

 whole in spirits of wine and follow out the treatment described for flies. 

 The piece of glass must, of course, be sufficiently heavy to sink the cork 

 in the spirits. Care should be taken in withdrawing the pin-points 

 when the spider is ready for transfer to spirits of turpentine. The 

 hardened balsam must first be dissolved, then the pin-points taken out 

 and the spider carefully removed from the cork. When quite clean 

 place it on another piece of cork or glass, and pin out as before and 

 put it into the turpentine bath, where it should remain until it is fit 

 for mounting in balsam. The pins should be about one-quarter of an 

 inch long and tolerably fine. In setting ants on the film of Canada 

 balsam their jaws will not always remain open. To prevent their 

 closing a small splinter of wood may be placed between the points of 

 them, which, if carefully done, keeps them well open. The precaution 

 is not necessary while they are in the turpentine bath. 



If it is desirable to keep insects for any length of time before 

 mounting them in Canada balsam, or if they have to be sent to a dis- 



