28 
Some Solitary Wasps of Texas. 
any more time deciding what to do next, but sets to work digging 
her nest, the tomb of her victim and the birthplace of her offspring. 
If the surface of the ground is dry and sandy, the hole is started 
by scratching out the sand with the front legs -as is usual with most 
digger wasps. These use their 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 rapidly, for Ammopliila 
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 
'opes (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 
down as far as one can see. Where the surface of the ground is 
