SEASONAL HISTORY. 



47 



from eggs laid in the cages, and these larvae, together with larvae 

 of the previous year, were carried through the winter in rearing 

 cages. 



The pupal records have been obtained from experiments in medium- 

 sized wooden boxes, having glass bottom, 9 inches long, 8 inches wide, 

 and 5 inches high (fig. 19). Each box contained 2 to 3 inches of 

 earth, and in order to duplicate outside weather conditions as nearly 

 as possible the soil in these boxes was permitted to become almost 

 dry during dry periods and during rainy periods water was propor- 

 tionately added. To exclude the light from below, the boxes were 

 placed upon burlap. Previous to the emergence of the beetles a 



wire screen cover was 



placed over each box. 

 The shallow layer of soil 

 caused many larvae to 

 penetrate to the bottom 

 of the cages, where they 

 appeared next to the 

 glass; and as the pupal 

 cells, made of earth 

 packed together, were 

 next to the glass the 

 activity of the insect 

 inside could be readily 

 observed. By means of 

 a glass and porcelain 

 blue pencil a number 

 was fixed next to each 

 cell, and by using this 

 number a detailed rec- 

 ord could be kept from 

 the time the cell was 

 made to the time the 

 adult emerged. In the study of the underground habits of the insect 

 the device shown in figure 20 proved to be useful. The glass cylin- 

 der in the earthen pot was about half filled with soil, and to exclude 

 the light the lower portion of the cylinder was wrapped with black 

 paper. Several cells were made next to the glass, and on emerging 

 the beetles were observed in the process of making their exit through 

 the soil. 



Cages similar to the one shown in figure 21 were convenient for the 

 study of the habits of the larva, and they were particularly useful 

 in experiments extending over periods of one and two years . In width 



Fig. 21. — Rearing cage with glass sides used in the study of 

 the larva of the grape root- worm beetle. (Original.) 



