no. 2173. A REVISION OF THE BEMBICINE WASPS—PARKER. 139 



in possession of a dead insect is met by one empty-handed. I have 

 frequently seen two wasps fight fiercely for the possession of a dead 

 insect that the victor, after gaining possession of it, discarded as not 

 worth carrying off. 



When leaving her nest the wasp invariably closes the opening, but 

 no very careful attempt is made to conceal the point of entrance save 

 when the visits for that day are complete. This species is preyed 

 upon by a number of parasites and this precaution of closing the nest 

 is doubtless to safeguard the nest against these enemies. They do 

 not, however, make any effort to close the entrance while within the 

 nest — a precaution that is practiced by both B. spinolae and B. nubil- 

 ipennis. 



During the six weeks within which these observations in the field 

 were recorded efforts were being made to rear the larval wasps, but 

 the final results were far from satisfactory. At first I took small bot- 

 tles filled with moist sand in which artificial cells were made wherein 

 eggs and larvae of different ages were placed. These were put in a 

 box and kept in the laboratory. While this work was in progress the 

 weather was very hot and every attempt ended in failure, the larvae 

 invariably dying before reaching maturity. This method was aban- 

 doned and a box filled two-thirds full of sand and provided with a 

 removable top was sunk in the sand so that the top was 4 inches below 

 the surface. In the sand within the box little pits were made and 

 stocked with eggs and larvae of various stages. The cover was placed 

 on the box and the whole apparatus covered to a depth of about 4 

 inches with sand. All went well for three days; conditions were 

 apparently as nearly normal as need be, but the third day a colony of 

 little red ants found my box and destroyed every vestige of my larval 

 wasps. The box was moved to what was deemed a safe place and 

 restocked. Things flourished for three days, when ants again found 

 the box and left not a trace of the wasps. I next secured shell vials 

 25 by 80 mm. which I partially filled with sand in which pits were 

 made for the reception of the eggs and larvae. A single egg or lava 

 was placed in each vial and a cork was loosely inserted to keep out the 

 ants and the vials were placed in the sunken box. This plan worked 

 quite well and I succeeded in rearing to maturity several larvae taken 

 at various stages of development and also in carrying two larval 

 wasps through from the egg to maturity and encasement. 



On July 17 a number of nests in process of construction were 

 marked and at 5 p. m. of the same day all these nests were completed 

 and closed, save one, which had been abandoned. On the morning 

 of the 18th three of these marked nests were opened before the wasps 

 were astir and each contained an egg in its characteristic position. 

 These were placed in the breeding box. One was destroyed by mi- 

 nute worms, a second was accidentally crushed by a fall of the vial, 

 but the third hatched. This egg was deposited on the afternoon of 



