238 



JOHN D. DODSON 



by 21 cm. wide, two electric boxes, D, D, each 15 cm. long by 10 

 cm. wide and two alleys, E, E, each 55 cm. long by 8 cm. wide. 

 The nest box opened into the entrance chamber by a small 

 doorway, F, closed by a vertically sliding door. The right electric 



K 



FIG. 1. CONTROL Box 



A, nest box; B, entrance chamber; D,D, electric boxes; E, E, alleys; F, G, G, 

 H, H, doorways, 7, /, food receptacles; J, K, lamp stand and lamp. 



box opened into the right alley and the left into the left alley by 

 the doorways, G, 6r, which were closed by colorless glass doors. 

 The alleys opened into the nest box by means of swinging wire 



