ARTHROPODA. 273 



2. Eggs : where deposited ? In what numbers ? Relation to 

 future food supply? 



3. Larval condition ("grub," "maggot," "caterpillar"). 

 Form, segmentation, general external characters, special 

 organs ; habits, food, coloration, enemies. 



4. Pupa (a resting and transforming stage) ; how pro- 

 tected? What is the origin and character of the protect- 

 ing structure? What changes are undergone at this 

 stage ? 



5. Adult. How do the larva and pupa compare with it in 

 segments, appendages, etc. 



The following forms may be studied and compared as to life 

 history : 



Squash-bug; all stages are to be found on squash, gourd, 

 cucumber and similar vines. 



Potato beetle; equally abundant on the Irish potato plant 

 in some years. 



Bees and wasps; to be found in their nests. 



" Blue-bottle " fly. This form may be studied in confine- 

 ment. (Expose raw meat for the eggs to be laid. 

 Place on a chip in a dish of moist earth or sand. Invert 

 a tumbler or bell-jar over it and watch the growth and 

 changes, as decomposition proceeds.) 



Mosquito. The larvae may be found in stagnant pools, 

 and watched in confinement. 



Cabbage butterfly. This form may be studied in the 

 garden, or in the laboratory by placing the cabbage 

 leaves with the larvae under a bell-jar and keeping the 

 conditions favorable. 



Some large caterpillar should be studied with some de- 

 gree of care in order to ascertain the general arrange- 

 ment of organs. 



Spider. If a mass of spiders' eggs can be found, the stu- 

 dent by watching may be able to determine whether the 

 development is direct or indirect. 

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