CONTENTS 9 



PROBLEM PAGE 



120. How animals may benefit mankind 148 



121. To find out how birds are of economic importance .... 148 



122. What are the causes of decrease in the number of birds ? . . . 149 



123. To study the life history of the mosquito ...... 149 



124. To find the breeding places of mosquitoes in any locality and how to 



destroy them 151 



125. To determine some methods of destroying mosquitoes . . . 151 



126. To find the relation of mosquitoes to diseases of man . . . 152 



127. To study the life history of the parasite causing malaria . . . 152 



128. To study the life history of the typhoid fly 153 



129. To determine the harm -done by the fly and the way it does this harm 154 



130. What is the best way to catch and destroy flies '? (Home work) . 155 



131. To determine harm done by insects ....... 155 



132. To know some forms of animal life that cause disease . . . 156 



XVI. THE FISH AND FROG, AX INTRODUCTORY STUDY OF 



VERTEBRATES ...... 159 



133. To determine how a live fish is fitted for life ..... 159 



134. To study food getting by the fish 161 



135. To study the sense organs of the fish ...... . 161 



136. 'J i' study some of the internal organs of a fish 161 



137. T , study the skeleton and central nervous system of the fish (Extra) 162 



138. 1 1 o,v fishes are artificially propagated 163 



139. Trip to the aquarium (Optional, in place of Problems 133 and 138) . 163 



140. To determine some adaptations in a living frog ..... 164 



141. Adaptations of appendages for locomotion 165 



142. Adaptations for sensation 165 



143. Adaptations for food getting . 165 



144. Adaptations for breathing ......... 165 



145. Museum trip to study the frog group (Extra problem based on trip 



to American Museum of Natural History) ..... 166 



146. To collect and study frogs' eggs 167 



147. To study conditions favorable for development of frogs' eggs . . 168 



148. To study the metamorphosis of the frog 168 



149. To work out a comparison of development of the vertebrates . . 169 



XVII. HEREDITY, VARIATION, PLANT AND ANIMAL BREEDING . 173 



150. To determine if there is individual variation in any one measure- 



ment of the members of a given class 174 



151. To show variation in a given class 176 



152. Does heredity play any part in our lives '.' ...... 177 



153. To study the fine structure of an egg cell . . . . . .178 



154. How selection is made ......... 178 



155. A practical result of selection ........ 179 



