66 STUDIES OF ANIMAL TYPES 



D. TOPICS FOR FURTHER STUDY. Write out a sum- 

 mary of the life history of a common mosquito. Compare 

 a mosquito with a locust in regard to the divisions of the 

 body, number of legs, eyes, antennae, and wings. Compare 

 its mouth parts with those of the locust. See Comstock's 

 " Manual for the Study of Insects " for the mouth parts 

 of a dipterous insect. To what branch does the mosquito 

 belong ? To what class, order, genus, and species does the 

 common mosquito belong. 



For information on the mosquitoes and their relation 

 to malaria and yellow fever, see Dr. L. 0. Howard's book 

 on mosquitoes. 



XX. THE PERCH 



Materials. A perch, black bass, or sunfish, live goldfish, dissect- 

 ing pans, scalpel, scissors, and piece of bread. 



Directions. (Although this exercise pertains especially to the 

 perch, the black bass, sunfish, or any other common fish will do with 

 very little modification of the outline. Small fish, such as minnows, 

 may easily be obtained from streams and permanent pools and 

 placed in aquaria for observation. In large towns and cities it is 

 often possible to have living goldfish in glass aquaria.) 



A. STUDY OF A LIVING FISH. What is the form of 

 the body? Is the form of the fish adapted to its life in 

 the water ? Is the tail symmetrical ? That is, is the dor- 

 sal lobe of the same shape and size as the ventral one ? 



How many fins has the goldfish? Where are they lo- 

 cated? How many single fins are there? Are any of 

 them in pairs? Watch the fish swim. What is the prin- 

 cipal organ of locomotion? Which fin is used most in 

 swimming ? Catch the fish carefully and place a light rub- 



