NO. 18 



SENSE ORGANS OF COLEOPTERA McINUOO 



IT 



The inside dimensions of the water screen (fig. 3, B) were 6 inches 

 Ijy 2 inches by 0.25 inch. The two pieces of glass (c) were held 

 securely one-fourth inch apart by a strong wooden frame (d). The 

 running water passed through a siphon (fig. 2, P) and a glass tube 

 (fig. 3, B, c), having a bore of one-eighth inch, into one end of the 

 water screen and out again at the other end through another tube 

 and siphon (fig. 2, Q, fig. 3, B. /). 



Fig. 3. — Diagrams of photo-geotactic box (A) and water screen (B), showing 

 following parts of them: a. glass shutter; b, wooden shutter; c, piece of glass; 

 d, wooden frame ; c, inlet glass tube ; and f, outlet glass tube. 



The lamp (fig. 2, O), consisting of a blue daylight bulb 100 W, 

 uoV, rested on the tal)le (E), or on a box, while the photo-geo- 

 tactic box and water screen lay on a stool (R). 



(c) RESPONSES OK ADULT BEETLES AND THEIR LARVAE IN DARK-ROOM 



Since the writer was not able quickly and acctu'ately to separate 

 the live bean beetles according to sex, sex was disregarded in all the 

 tests conducted. The beetles, otherwise, were selected so that those in 

 each set were of practically the same age and responded to daylight 

 readily. 



