Some Solitary Wasps of Texas. 13 



down as far as one can see. Where the surface of the ground is 

 soft and dry, the hole will be wide-mouthed like a funnel, due to 

 the caving in of the sides. 



On cross-sectioning the nest its true shape is revealed. The gal- 

 lery, nearly vertical near the top, runs down in a gentle curve till it 

 becomes nearly horizontal, where it widens out into a spacious 

 pocket which received the caterpillar. Fig. 23 represents a nest of 

 average size and typical shape. The distance from the mouth to 

 the farthest end of the pocket is three inches; this is % inch high 

 and 11/4 inches from the surface of the ground and the tunnel is % 

 inch in diameter. The pile of excavated sand at the left is 3 inches 

 from the entrance. Fig. 17 represents two smaller nests also dug 

 by large individuals. The nests are of a different shape from the 

 typical. Both have short tunnels ; the pockets, one inch below the 

 surface of the ground, have their long axes at right angles to the 

 tunnels. 



After the completion of the nest, the next problem confronting 

 Mme. Ammophila is the procuring of a supply of food for her 

 future offspring. Caterpillars always constitute the victim of the 

 Ammophilae, and the number varies with the species of the wasp 

 and the size of the caterpillars. The large individuals of procera 

 capture and store but one immense green "tomato" caterpillar, 

 the subject of the photographs. The smaller store several small 

 caterpillars of about the same length of their own body. 



Before setting out on the chase, some species of Ammophila take 

 the precaution of making a temporary closure of the nest, particu- 

 larly if the provisioning is to be postponed to the next day, and 

 the degree of care with which the closure is effected varies with 

 the species and with the individual. A lump of earth may be 

 laid over the entrance and this covered with a number of pellets 

 so as to make the location indistinguishable. Another individual 

 of Ammophila urnaria has been observed by the Peckliams to wedge 

 a good sized stone deep into the neck of the burrow and then fill 

 the space above, solidly, with smaller stones and earth. A 

 third individual of the same specie neglected to close the nest 

 at all. Fabre describes Ammophila argentata and Ammophila 

 sabulosa as closing the nest immediately after it has been made^ 

 but Ammophila holosericea as leaving it open until it is com- 

 pletely stored. The last mentioned species stores five to six cater- 

 pillars, and Fabre thinks she leaves the nest open on account of 

 the inconvenience of closing it so often. Dr. Williston, however, 



