Method of Mounting Heads of Insects without Pressure. 145 



A strand of very fine silk was tlireaded tlirougli each needle, 

 which were then thrust right through the head, and on being 

 withdrawn left the two strands of silk with the ends at equal 

 distance on either side of the head. 



A ring of cement having been spun on the top of the cell a 

 little glycerin solution is run, with a brush, all round and on the 

 bottom of the cell ; the ends of the silk, with the head suspended, 

 are stretched out at equal distance across the cell, on to which they 

 are lowered and embedded in the cement on each side. The cell 

 is then filled with glycerin solution to well above the top in its 

 convexity, on which a perfectly clean cover glass is carefully 

 lowered and gently pressed down until ii rests firmly on the cell, 

 the pressure being kept up by a small weight placed on the cover 

 glass until the cement dries. 



For this purpose I used conical bullets. 

 • The excess of glycerin fluid may be brushed off, but no attempt 

 should be made to clean the slide until after the cover glass 

 has become firmly attached to the cell by the drying of the 

 cement. 



The ends of the silk are then cut off, and the slip carefully 

 washed and dried. 



Mr. Enock made use of a trough of wood, 12 in. long and 

 slightly over 3 in. wide, into which his mounts were placed, and 

 left until dry. 



If it be not desired to secure the head with silk, a little of the 

 glycerin solution is run, with a brush, all round and on the bottom 

 of the cell, as before ; the head is placed in and arranged on the 

 bottom of the cell, which is then filled, and closed, as before. 



The slide is finished by spinning several coats of cement round 

 the side of the cell and upon the edge of the cover glass, each coat 

 being allowed to dry hard before the next is applied — and to 

 perfectly seal the cell don't spare this part of the operation. 



Such was Mr. Enock's beautiful method of mounting. One 

 word — don't be dismayed at failures, for only practice can accom- 

 plish perfection ; but the beauty of a successful mount is compensa- 

 tion indeed, for it is science and art in that small cell. 



In conclusion I append a few notes. 



1. The heads should be set before they are fixed in rigor mortis^ 

 as they cannot then Ije relaxed. Mr. Enock suggested that all 

 insects be kept in crushed laurel leaves, which will keep them 

 relaxed for a short time, but they should be set out as soon as 

 possible. 



2. It is impossible to clean a wasp's tongue. Put it under aii 

 inch power and you will see why it is so — those numberless hairs 

 in each cell of the tongue hold all impurities, and you cannot get 

 them away. If possible get queen wasps and hornets, for they 

 have fasted all through the winter and their tongues are beautifully 



