BULLETIN 39, UNITED STATES NATIONAL MUSEUM. [130] 



Spiders and mites thus collected may be transferred to alcohol. Dr. 

 Marx, who has had a very considerable experience in the preservation 

 of spiders, recommends the use of the following mixture: Glycerin 

 and Wickersheim's fluid, 1 J ounces of each, and distilled water 3 ounces^ 

 the whole to be shaken and thoroughly mixed and added to 30 ounces 

 of 95 per cent alcohol. Alcohol which has previously been used for pre- 

 serving spiders, and which has therefore dissolved some of the fatty 

 matters from the specimens, he prefers to pure alcohol, using with this, 

 however, somewhat less of the distilled water. The liquid thus com- 

 posed answers all demands and keeps the specimens flexible and pre- 

 serves their coloring. Should the stopper become loose and the liquid 

 evaporate, there is always sufficient hquid, water or glycerine, left in 

 the vial to keep the specimens from drying and thus save them from 

 destruction. Dr. Marx also prefers to use cork stoppers rather than the 

 rubber stoppers recommended for other alcoholic material. His objec- 

 tion to the rubber stopper is that, in a collection in which the specimens 

 are often used and the stoppers are frequently removed, he finds that 

 small particles of the rubber stopper come off and settle upon the speci- 

 mens as a white dust, which it is difficult to remove. This objection 

 applies only to a poor quality of rubber, and in all other respects the 

 rubber is much to be preferred. The colors of spiders are apt to fade 

 somewhat if exposed to light, and the collection should therefore be 

 kept in closed boxes or in the dark. 



COLLECTING MYRIAPODA. 



Centipedes and Millipedes are collected in the same manner as 

 spiders. They live in damp places, under sticks and stones, and in 

 decaying vegetation. They should be preserved in alcohol, and on 

 account of their usually strong chitinous covering, precautions as to 

 the strength of the alcohol are less necessary here than with softer- 

 bodied specimens. 



The members of this subclass comprise a number of well-marked 

 groups. The lulidse are cylindrical insects and occur in moist places, 

 as do most of the representatives of this subclass. A common form 



is represented in the accompanying 



.*«^^W?f^^§Bs=„==„e-=sf^^^^^^fes. figure. The Chiliopodse comj)rise 



^^f!^^^^I[^^fftii^^^^^^^W\ ^^^ flattened forms having many- 



'''^•' /;%/,////^;;>/>;;/,'////''''''''''f jointed antennae and but a single 



pair of limbs to each segment of 

 the body, and are the forms to 

 which the name centipede may properly be applied. They are preda> 

 ceous in habit, live largely on living animal matter, and are very quick 

 in their movements. Some forms are poisonous, having poison glands 

 at the base of the first pair of legs, but the majority of the species are 



Fig. 139. — A Milliped (Camhula annulata). 



