Some Solitary Wasps of Texas. 49 



the length of the wasp's body. Fifteen to twenty seconds was suf- 

 ficient time for the wasp to apply each load of mortar carried home. 

 After the required length of the celL which now looked a good deal 

 like a barrel lying on its side, had been reached, the inside was 

 carefully plastered and calcimined with a number of pellets of mud, 

 the wasp reaching in for her whole length and at times working 

 upside down. Possibly the wasp was adding an extra amount of 

 saliva to this last work thereby manufacturing a kind of varnish 

 with which to increase the durability of the structure. At any 

 rate the interior presents a smooth surface while the exterior is very 

 rough, each elevation representing the amoiint of mud brought in 

 by a single load. 



At 5 :15 the cell was ready to receive the spider with which it was 

 to be stored. Mellipes, however, does not have good luck in find- 

 ing the spiders she wants. On this occasion it took her twenty- 

 four hours to store the cell, on another forty-six hours elapsed be- 

 tween the completion and tl^.e storing. At 6 :30 p. m., August 1, 

 the wasp was just putting the finishing touches on the disc-shaped 

 lid with which she closed the cell. I failed to catch the wasp at 

 this time though I succeeded ten days later while she was at work 

 under another leaf in the same angle of the elm tree roots. 



The wasp had built three barrel-shaped cells tapering slightly at 

 both ends, each cell about eight mm. long and four in greatest 

 diameter. One cell was independent of the other two which were 

 built together at an angle of about 120 degrees. The angle seems 

 to depend on the conditions under which the cells are built, for 1 

 once found in a narrow crease of a wagon cloth five cells of melUpes 

 attached one to the other in a straight line. Having reached home 

 with my trophy I could not resist opening at least the cell last 

 made to ascertain the condition of the spider and the position of 

 the egg. Both are well shown in Fig. 20. The spider, it will be 

 seen, had lost all its legs but the front pair and the egg was placed 

 across the ventral surface of its abdomen. The spider was stuffed 

 into the cell head first. 



But egg and spider were not the only occupants of the cell. To 

 my great astonishment I became aware of a tiny parasitic wasp, 

 no larger than Agenia's egg itself, resting on the egg. The para- 

 site (Ophelinus florifrons,, Ashm.) had been imprisoned and when 

 I found it, was evidently about to infect the egg of its host. It 

 had not yet laid its own eggs into that of melipes, however, for the 



