54 FIELD ZOOLOGY. 



After the wet plaster of Paris has been run in so as to cover 

 the mixture completely, leave the bottle in the open air 

 for two hours or less according to the dryness and heat 

 of the outer air; it will then be sufficiently dry, and after 

 that must be kept carefully corked except when putting 

 in your finds that are to be killed. 



The usual reservations must be made in the use of 

 this bottle ; no beneficial insects are to find their way into 

 it unless it is past their season of usefulness; small and 

 large insects must not be put into it together, as their 

 struggles are apt to injure the smaller, weaker ones; and 

 insects put into this killing bottle must not be left too 

 long without attention. This same precaution should be 

 observed with respect to the . chloroform killing bottle; 

 there is a tendency with some insects, for the muscles to 

 stiffen if they are left two hours or such a matter in the 

 fumes of chloroform. There seems not to be this fault 

 with the ether. When the cyanid bottle is opened it 

 should be in an open room ; and the killing bottle should 

 not be left habitually in one's sleeping-room. This last 

 precaution is given because it is often advisable for each 

 student to have a killing bottle of whichever kind the 

 instructor may deem the best. 



The wings of butterflies and grasshoppers are part 

 of the requisites for finding out what kinds of butterflies 

 and grasshoppers you have; hence it is necessary to set 

 them up in such a way that their wings show well. A 

 dr)ang board is useful in this case. Take two small 

 pieces of inch lumber, eight inches long by four inches 

 wide. Saw a V-shaped piece out of the long side of each 

 of these two pieces, with a slope of the sides at an angle 

 of 25° to the edge of the piece of lumber. Do not make 

 the V too sloping; this angle determines the angle of the 



