CHAP. XXII. HOW TO COLLECT AND PRESERVE INSECTS. 149 



I 



tight, so as to prevent small insects, mites, etc., from gaining 

 access to and spoiling the collection. The cork or pith in the 

 bottom of the boxes should be covered with white paper, 

 which, if lightly cross-ruled, will greatly facilitate the regular 

 pinning of the specimens. 



For relaxing dried insects, place them for twelve or twenty- 

 four hours in a tin box containing a quantity of moistened 

 sand over which first a single layer of paper is spread ; their 

 wings, etc., can then be easily spread out. 



Caterpillars, grubs, pupae, and similar objects may be pre- 

 served in alcohol. They should first be thrown into alcohol 

 diluted with water, and afterwards be removed to vessels con- 

 taining alcohol of full strength. 



Nothing is more annoying to the experienced, or more dis- 

 couraging to the young collector, than to have his specimens 

 destroyed by mites, or by the Iarva3 of certain beetles; against 

 the ravages of these pests there is no security. Paste and 

 paper fail to exclude them; camphor is only a partial pro- 

 tector; and the only safeguard is constant vigilance, and the 

 instant destruction of the offenders when observed. 



For this purpose many methods have been suggested, such 

 as saturation with turpentine, immersion in alcohol or ben- 

 zine, exposure in an oven to a heat of 210, etc., but most of 

 these means are liable to injure or even destroy the specimens. 



A very good method, however, is to place a galipot or small 

 saucer, containing about twenty-five grains of cyanide of 

 potassium, roughly bruised, with a very little water, in the 

 bottom of the cabinet; drop about six drops of sulphuric 

 acid upon the potassium and close up the cabinet. The gas 

 thus generated will destroy the life of any larva, or other 

 insect or animn.1, that may be in the cabinet at the time, as no 

 animate being can inhale this gas and live. Great care should, 

 therefore, be taken to prevent the inhalation of this gas by 

 the person employing it. 



