REARING AND COLLECTING ANIMALS 



471 



ment the mature insects are apt to emerge in mid-winter. 



"An excellent breeding-cage is represented by fig. 239. It 

 is made by combining a flower-pot and a lantern-globe. 

 When practicable, the food-plant of the insects to be bred 

 is planted in the flower-pot; in other cases a bottle or tin can 

 filled with wet sand is sunk into the soil in the flower-pot, and 

 the stems of the plant are stuck into this wet sand. The top 

 of the lantern-globe is covered with Swiss muslin. These 

 breeding-cages are inexpensive, 

 and especially so when the pots 

 and globes are bought in con- 

 siderable quantities. A modifi- 

 cation of this style of breeding- 

 cage that is used by the writer 

 differs only in that large glass 

 cylinders take the place of the 

 lantern-globes. These cylinders 

 were made especially for us by a 

 manufacturer of glass, and cost 

 from six to eight dollars per doz- 

 en, according to size, when made 

 in lots of fifty. 



"When the transformation of 

 small insects or of a small num- 

 ber of larger ones are to be 



studied, a convenient cage can Fig. 239. Lamp-chimney and 



be made by combining a large flower-pot breeding-cage for 



lamp-chimney with a small "^sects. 



flower-pot. 



"The root-cage. — For the study of insects that infest the 

 roots of plants, the writer has devised a special form of breed- 

 ing-cage known as the root-cage. In its simplest form this 

 cage consists of a frame holding two plates of glass in a verti- 

 cal position and only a short distance apart. The space 

 between the plates of glass is filled with soil in which seeds 

 are planted or small plants set. The width of the space be- 

 tween the plates of glass depends on the width of two strips 

 of wood placed between them, one at each end, and should 



