Holmes, The Reactions of Ranatra to Light. 



333 



travel to the light in a more direct course. A Ranatra with its 

 right eye blackened over was placed on the top of a table three 

 feet away from an incandescent lamp. Each time the specimen 

 reached the lamp it was picked up by its breathing tube and 

 placed in its original position facing the light. The course over 

 which it traveled was in each case followed by a pencil. The 

 paths taken in successive trials are represented in the accom- 

 panying diagram (Fig, 4). 



Fig. 4. Paths taken by a Ranatra in successive trips to the light. The 

 position of the lamp is indicated by a dot at the upper side of each path. The 

 cross lines indicate places where the insect took wing. When it flew directly to 

 the light its course is represented by a dotted line. At A the experiment was 

 discontinued for fifty minutes, after which the remaining tracings were taken. 



The specimen showed a strong tendency to fly as it drew 

 near the light, and after the tenth trial its wing covers were 

 stuck down by asphalt varnish. After a few ineffectual attempts 

 to raise the wings the insect gave up trying to use them and 

 walked to the light more quickly and with fewer pauses. The 



