S. GREEN ON PREPARING INSECTS FOR THE MICROSCOPE. 225 



then with a line 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 in- 

 sect 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 hardened film will 

 be found sufficiently dense and strong to keep the legs and wings 

 of the insect in the position they were originally placed 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 sufficiently transparent for mounting in Canada 

 balsam. I have been very successful with spiders, but there are 

 some species 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, as I have nearly always found. 

 The palpi and mandibles may be also kept in proper 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 



