23 



•3. Test them with various kinds of food. 



4. Note the development of the legs. 



5. What becomes of the tail ? 



6. Examine its eyes. Has it any eye-lids ? 



7. Study the habits of the frog-. 



8. What does it eat ? 



9. How does it breathe ? 



10. Does it ever drink ? 



« 



11. Experiment. Dreprive a toad of water for a day and weigh him 

 carefully. Next sit him on a wet blotting paper for an hour or two and 

 weigh again. What is the increase in weight due to ? 



12. Note its humpbacked body and its sitting posture. 



13. ^^'hat are the natural enemies of tadpoles ? 



14. What are the natural enemies of the frog ? 



15. Since so many eggs are laid by each female frog, and nearly all 

 these produce tadpoles, how do you account for so few frogs ? 



16. Of what economic vali!ie are toads ? 



IT. Write a short account of the life history of the toad, and com- 

 pare with that of the frog. 



18. How many kinds of frogs in your vicinity? 



XXXVII. Mosquitoes. 



1. Collect some larvae of mosquitoes in stagnant water, and place 

 them in a glass jar for observation. 



2. Watch carefully the habits of the larvae, — how they breathe, how 

 they swim, and whether heavier or lighter than water. 



3. Make drawings of the larvae. 



4. How long do the mosquitoes remain in the larval stage? 



5. Study carefully the pupa stage, — how it differs from the larval, 

 how it breathes, etc. 



6. Watch the escape* of the adult mosquito. Describe the oper- 

 ation. What state of water is necessary ? 



7. Are all the larvae exactly like ? the pupae ? the adults ? What 

 difference between the male and female ? 



8. Secure specimens of Culex, of Anopheles, both males and females. 



9. Try simple experiments on the killing of the larvae with oil. 



10. Endeavor to get the eggs of mosquitoes. .Draw the egg mass. 



11. Ascertain the exact duration of the different stages of the mos- 

 quito. 



