192 ELEMENTARY LESSONS ON INSECTS 



the school itself. It should be begun by one class and con- 

 tinued by succeeding classes. It should grow; it should not 

 be bought. The only things purchased for it should be the 

 equipment and supplies necessary for the making of it. 



It should be in part an exhibition collection of local insects, 

 neatly mounted and labelled with both common and scientific 

 names, and kept in glass-topped boxes on accessible shelves. 

 Every collecting trip will yield materials for it. To be of 

 use to the community it should be made as complete as 

 possible in local economic species. 



The school collection should be in part a study collection, 

 containing: 



1. Reserves of specimens, gathered when abundant and 

 stored either in papers, or in alcohol. There are important 

 groups of insects, like cicadas and mayflies and caddisflies, 

 adults of which are easily obtained from summer swarms, 

 but not so easily during the school year. 



2. Slide mounts for showing structural details. These 

 should be prepared in sets, in numbers sufficient for class 

 use, and stored in slide boxes, plainly labelled. Some slides 

 should be prepared by each pupil, and the best from each 

 year should be saved and added to the collection. 



3. Reserves of living materials, gathered each autumn for 

 use during the following winter. These are best kept out- 

 doors; the simple wire cloth cages described on page 200 will 

 keep most of them, whether terrestrial or aquatic. In a dry, 

 heated school building most of it will die of evaporation. 

 But transformation may be hastened by a stay indoors, and 



