58 Some Solitary Wasps of Texas. 



empty shot-gun shells standing upright. In these the partition 

 and the plug were each in two layers, an inner of white and an 

 outer of yellow clay, each layer being a millimeter in thickness. 

 In getting the nest ready the only thing I have seen texense do is 

 to plaster a few pellets of mud against the bottom of the tube. 

 Thus the cap hole of the shot-gun shell was tightly closed with it. 

 The length of the chambers depends on their calibre and varies 

 from three-fourth inch to one and one-half inches. When a nest 

 is composed of several cells in horizontal series, the partition is 

 built from the bottom up and is therefore thickest at the bottom. 

 In closing the last chamber an extra amount of mud is plastered 

 on and the plug is brought flush with the surface. In about half 

 the cases the final closure was made with two plugs from one-fourth 

 to one-half inch apart leaving an empty space or false chamber be- 

 tween them. This must certainly be an effective means of de- 

 ceiving such parasitic enemies (should they have any) as lay their 

 eggs by means of boring ovipositors into the nests of their aculeate 

 hosts. 



T. texense has a way, as I have already pointed out above, 

 in connection with Agenia subcorticalis, of economizing time in the 

 matter of getting mortar for the nest. I had always thought that 

 this was gotten from the moist banks of the creek or river, whither 

 Pelopaeus pilgrimizes for her building material. But it is certain 

 that many do not get mud from that source but instead take it 

 from the nearest place obtainable, namely those great pyramids of 

 the world of wasps, the abandoned mud-dauber's nests just at hand. 

 Soon after I had begun inducing texense to make her home with 

 us and build her nests on the gallery of the Lucksinger country 

 home, the old mud-dauber nests began to decrease perceptibly in 

 size, their material being used again in similar architectural enter- 

 prises. Trypoxylon flies from her nest to a suitable place on a 

 mud-dauber's nests and begins to gnaw off a piece of the dirt with 

 her mandibles moistening it with saliva as she works. Pelopaeus' 

 old house is hard and one can hear the grating and clicking of 

 Trypoxylon s mandibles upon it as well as the hum of her wings 

 under the strain of her work. Finally a pellet as large as her head 

 is loosened and the wasp, just as the pellet is ready to drop, catches 

 it "under her chin," as it were, and takes it to her nest. The dirt 

 Is moist when plastered on and one can see the moist spot from 



