NEST OF ODYNERUS — CLARK AND SANDHOUSE 93 



On March 26 a female was placed in a large jar with a heap of 

 mud at one side of the bottom on which was a small pool of standing 

 water, a sprig of flowering cherry, and a forked privet twig. The 

 day was cloudy, and after moving about the jar in a desultory way 

 for about an hour the wasp came to rest behind the bottle of water 

 holding the twigs. The next day was rainy, and the wasp spent the 

 day at the top of the privet twig resting with the tip of the abdomen 

 touching the twig and the body making an acute angle with it, and 

 the forelegs drawn up close to the body. 



On the day following the wasp came to the mud at 9 a. m., rested 

 on it for about half an hour, then crawled up the privet twig to the 

 cloth. Wlien sunlight entered the jar the wasp became very active, 

 but spent most of its time on the sunny side of the jar, showing no 

 interest in the mud. It died the next day. 



The four remaining females were transferred to the large jar on 

 March 30. None of them showed any interest in the mud. 



The fii^t female to emerge died on March 31; she retained her 

 bad disposition to the end, from time to time hovering near and 

 pouncing upon the others. 



The last surviving male died on March 26. 



The three remaining females were transferred to petri dishes on 

 March 31 for the purpose of subjecting them to experiments with 

 light. All three were found dead on April 3. 



After being placed in a petri dish 150 mm in diameter and 20 mm 

 high with white blotting paper covering the bottom, each of three 

 females at the first opportunity (two days later) made a complete 

 examination of the container, running rapidly and irregularly about 

 and investigating every portion of the bottom, top, and sides. 



In one petri dish there was on the blotting paper a small blackish 

 spot with a light border about 2 mm in diameter situated 50 mm from 

 the edge. This was promptly discovered by the wasp, which sud- 

 denly stopped and whipped down the antennae so that the tips almost 

 or quite touched it, remaining motionless for a second or two. It 

 then started off again but soon returned to the spot, remaining for a 

 short time motionless as before. Every few seconds, after running 

 irregularly about over the blotting paper, it would rush directly to 

 the spot, depress its antennae, and remain motionless. The intervals 

 between the examinations of the spot gradually became longer, but 

 not until it had approached the spot from every direction did it cease 

 making occasional dashes to it. 



After the wasp had thoroughly and completely studied the loca- 

 tion and nature of the spot, it developed an interest in a small area 

 at the edge of the dish where the blotting paper was turned upward 

 and frayed. Previously it had paused here a few times in passing; 

 but now it turned its entire attention to this region, occasionally leav- 



