292 C. H. TURNER. 



was watched. It moved backward in jerks. The hind legs, which 

 were doubled back under its abdomen, made jerky pulls. The 

 middle pair of legs was directed outwards in almost a straight 

 line. The anterior pair of legs was stretched forward. The 

 tips of both the first and second pair of legs touched the glass. 

 The mandibles took no part in the movement. 



Experiment 2. The ant-lion was placed on the glass plate and 

 held, in a horizontal position, above my head; so that I could look 

 up. at it with a magnifying glass. The results were the same as in 

 experiment I ; but it was easier to observe that the tips of all 

 the legs touched the glass. The third pair of legs was the only 

 pair making vigorous movements. 



Experiment j. / tilted the glass plate so that the posterior portion 

 of the ant-lion was uphill. When the angle became steep the ant- 

 lion fell. 



Experiment 4. Repeated number i, substituting a pasteboard 

 rectangle for the glass plate. The result was the same as in ex- 

 periment i ; but the insect moved faster. 



Experiment 5. / tilted the paste-board rectangle so as to have the 

 posterior portion of the insect up-hill. Even when it had reached 

 an angle of 90 degrees, the insect retained its hold. It moved 

 upward, sidewise and downward. 



Experiment 6. While the cardboard rectangle was inclined at a 

 steep angle and the ant-lion was resting head downward, with a 

 dissecting needle, I raised the tip of the abdomen from the support. 

 The ant-lion retained its hold. 



These experiments show conclusively that the mandibles do 

 not assist in locomotion ; at the same time, they indicate that the 

 hind pair of legs play an important role. Yet, so far as these 

 experiments go, the hind legs might be mere grappling hooks to 

 prevent the creature from slipping forward and the real locomotion 

 be due entirely to the flexing and stretching of the abdomen, all 

 forward motion being prevented by the stiff bristles on the sides 

 of the body and the grip of the legs. 



Experiment 7. A layer of dirt eqiial to the height of the greatest 

 height of the ant-lion was spread on a glass plate. The ant-lion 

 was placed on this pile of dirt. The larva began to burrow back- 

 ward into the dirt; but made practically no progress. By the 



