I0 INSECT LIFE. 



swims through the water; and an insect that sucks 

 the blood from its victims has a different kind of 

 mouth than one that chews up the leaves of plants. 



It is also important that we should know the 

 names of the principal parts of the body of an insect, 

 so that we may understand descriptions of insects, 

 and be able to write descriptions ourselves. 



We have selected locusts, or grasshoppers as they 

 are more commonly called, for the subject of these 

 introductory lessons. We have done this because 

 locusts are quite large, and are common in all parts 

 of our country ; and, too, the parts of the body in 

 these insects are comparatively simple. 



In the course of these lessons the following things 

 will be needed : A supply of locusts,* blank paper 

 and pencils for making notes and drawings, one or 

 more cyanide bottles (see page 286) for killing the 

 specimens collected by the pupils, a lens, cardboard 

 and mucilage for mounting dissections, and scissors. 

 A compound microscope is very desirable, but not 

 absolutely necessary. 



* It is best, when practicable, that the pupils should collect these for 

 themselves. But in the case of city schools, or when the work is begun 

 at a season of the year when these insects are not readily found, the 

 teacher should have on hand a supply of locusts preserved in alcohol. 

 These can be collected beforehand or obtained of some dealer in labora- 

 tory supplies. The best way to collect them is by sweeping (see page 291) 

 the grass in a dry meadow or pasture in late summer or early autumn. 

 In this way a pint or more of locusts can be collected in a short time. 

 These can be preserved in alcohol in an ordinary glass can, such as is 

 used for preserving fruit. There should be more than enough alcohol to 

 cover the insects, and after they have been in it for twenty-four hours it 

 should be poured off and fresh alcohol substituted. A list of dealers in 

 laboratory supplies is given at the close of this volume for the conven- 

 ience of those who wish to purchase specimens. 



