12 Some Solitary Wasps of Texas. 



After the location has been chosen, Ammophila does not waste 

 any more time deciding what to do next, but sets to work digging 

 her nest, the tomb of her victim and the birtliphice of her offspring. 

 If the surface of tlie ground is dry and sand}', the hole is started 

 b}' scratching out the sand with the front legs as is usual with most 

 digger wasps. These use tlieir front feet during the whole digging 

 process, employing their mandibles only to bite loose the more solid 

 earth or to break up the larger lumps. If the ground is hard at 

 the surface, Ammophila begins by biting off pieces of earth and 

 carrying them to one side, continuing this method until the nest is 

 finished. The need of this mode of excavation as compared with 

 the scratching method employed by most digger wasps becomes ap- 

 parent when the shape of the nests are taken into consideration. 

 The tunnel leading to the pocket of Ammophila' s nest is nearly ver- 

 tical (Figs. 22 and 18), while the nest of other digger wasps is a 

 nearly horizontal tube with a slight dilation at the end (Figs. 19 

 and 21. Fig. 6 represents Ammophila beginning her nest by bit- 

 ing the ground loose with her mandibles. Fig. 13 shows the nest 

 farther advanced with the wasp already reaching down to bite off a 

 "mouthful" of dirt. The work progresses rapidh% for Ammophila 

 is a zealous and steady worker. Only now and then does she fly up 

 and circle about a little to fix the locality of the nest in her mind. 

 At first sixteen to eighteen loads of earth are carried out a minute, 

 and as the nest deepens the time required for going in and out in- 

 creases, so that as the nest nears completion, only eight to ten trips 

 are made to the surface per minute. The wasp goes down the hole 

 head first and backs out, turning around at the surface and run- 

 ning over to the dumping ground a few inches away. Here 

 the load is flung down with a flirt accompanied by a joyful, enthusi- 

 astic buzz. After thus hurling away the lump of earth Ammophila 

 gives a jump, turning suddenly face about, and goes back, half run- 

 ning, half flying, after another load. Fig. 22 shows the pile of sand 

 carried out by the wasp on the left of the picture, i. e., on the side 

 of the nest opposite the pocket towards which the entrance gallery 

 slopes (at x). 



The work of excavation occupies about thirty-five minutes in the 

 loose soil of the woods where the observations were made. The com- 

 pleted nest, in general always characteristic of the species, varies 

 somewhat with the individual and the condition of the soil in which 

 it is dug. From above (Fig. 8) the nest appears as a perfectly 

 round hole about half an inch in diameter leading nearly straight 



