54 WASP STUDIES AFIELD 



The hole (see fig. 10, exact size), one-fourth inch in 

 diameter, went downward at an angle of 40 degrees with 

 the surface level, for about two inches, and terminated in 

 an oval, horizontal chamber an inch long and a half -inch 

 wide. 



From these observations we may be sure that the egg was 

 deposited and the spider entombed at about 1 1 : 45 a. m. 

 At 10 o'clock that evening the spider was active and would 

 make the characteristic threatening spring back when 

 touched. The legs could move actively but not coordinately, 

 and were unfit for progression; the mandibles attempted to 

 close, but could do no more than quiver, when tickled with 

 a straw. After this activity we were surprised the next 

 morning to find it dead. By the following day we were 

 quite certain that the egg too was dead. 



One mid-September morning we saw a lot of dirt thrown 

 out of a hole in the side of a depression made by a horse's 

 hoof. As we came nearer, a P. tropicus emerged and flew 

 away in alarm, but slowly returned, found the spot and en- 

 tered. Thus she fled in affright and timidly returned three 

 times, when we tried to come near enough to observe her 

 activities. She jumped into the hole which then lacked 

 only a half -inch of being full, bit away the soil from around 

 the edge of the irregular hole and dropped it in. Still the 

 wasp was so nervous and suspicious that only with the 

 greatest caution could we get near enough to see what she 

 was doing. She often flew out, frightened, then nervously 

 flapped her wings, walked in again and continued her task. 

 At last we could creep close enough to see her smoothing 

 down the filling in the hole with her abdomen, but in a 

 strange way quite new to us. The abdomen was curled 

 under the body, making the dorsal surface of the tip appear 

 ventral; this convex portion, pressed against the ground, 

 proved a very efficient sad-iron, smoothing and at the same 

 time compressing the loose soil. 



