Insect Study 



Z^Z 



the recluse is now a creature 

 of the outside world. 



Many galls are compound, 

 that is, they are made up 

 of a community of larvffi, 

 each in its own cell. The 

 mossy rose-gall is an instance 

 of this. The galls made by 

 mites and aphids are open 

 either below or above the 

 surface of the leaf; thelittle 

 conical galls on witch-hazel 

 are examples of these. In fact, each gall has 

 its own particular history, which proves a 

 most interesting story if we seek to read it 

 with our own eyes. 



LESSON LXXIX 

 The Gall-dwellers 



Mossy rose-gall. 

 Comstock's Manual 



Leading thought — ^The galls are protective 



habitations for the little insects which dwell 



within them. Each kind of insect makes its 



own pecuhar gall on a certain species of plant, and no one understands 



just how this is done or why it is so. 



Method— Ask the pupils to bring in as miany of these galls as possible. 



Note that some have open doors and some are entirely closed. Cut open 



a gall and see what sorts of insects are found within it. Place each 



kind of gall in a 

 tumbler or jar 

 covered with cheese- 

 cloth and place 

 where they may be 

 under observation 

 for perhaps several 

 months; note what 

 sort of winged insect 

 comes from each. 



Observations — i. 

 On what plant or 

 tree did this gall 

 grow? Were there 

 many like it? Did 

 they grow upon the 

 root, stem, leaf, 

 flower, or fruit? If 

 on the leaf, did they 

 grow upon the pet- 

 iole or the blade? 



2. What is the 

 shape of the little 



Porcupine gall on 

 leaf of white oak. 



Section of same 

 shoiiiug cells. 



Photo by C. J. Triggerson. 



Female gall- 

 fly I a y i n g 

 eggs in oak 



hud. 



