robison] TIME ECONOMY AND TEACHING DEVICES 127 



wing. Even when done on a moist plate, the folds persist in fly- 

 ing back into place, which, of course, illustrates some features of 

 its workings. Many such features must be made out, if at all, on 

 material that may be torn with impunity; but students cannot 

 advantageously use such material for the study of many points. 



The time-saver described below has been satisfactory in some 

 respects. 



On a glass slip are placed the following: (a) upper wing 

 of locust, (b) under wing folded naturally, (c) under wing 

 spread. These are fastened with glue until they can be covered 

 with another slip and the two fastened with passe partout. The 

 best binder is the kind used for lantern slides, especially that put 

 up in ten-yard rolls. The joint of the giant waterbug's upper 

 wing is so thick that the slips do not bind well unless separated at 

 one end by one or two thicknesses of an eighth-inch strip of card- 

 board. Half of the locust preparations might be some species with 

 edged under wings, as the Carolina locust, and the other half, a 

 species with clear under wings, like the red-legged locust. The 

 label may be pasted in before the slips are bound together. 



Readers of the early numbers of the Nature-Study Review 

 will easily trace the writer's idea to the article, "Nature-Study 

 with Insects", by Professor Hodge, in vol. 2, no. 8, (November, 

 1908) pp. 265-270.* A surprisingly large number of well-informed 

 teachers have not heard of the method there described of taking 

 care of insects in small units, for it is common experience that a 

 case of fifty insects is not of the practical value it should be. 

 Normal schools may often easily get good collections from their 

 state agricultural colleges or state entomologists at a cost of a 

 few cents a specimen, especially if containers for shipment are 

 sent by the purchaser. Such collections may be broken up and 

 one or two specimens placed in a case, even though the student 

 has not himself collected the stages of a life-history, as was Pro- 

 fessor Hodge's purpose. 



For the present reference his method may be briefly sum- 

 marized. Spoiled photograph negatives, 4x5 or other standard 

 sizes, are used as top and bottom of a case whose sides are formed 

 by a thin wooden strip notched to allow it to be bent at the cor- 

 ners, the glass being fastened by binding strips. If the glass is 

 not also glued to the wooden strip as suggested, it is easier to open 



*Although vol. 2 is out of print, the November number can be 

 obtained. 



