90 PROCEEDINGS OF THE NATIONAL MUSEUM vol.84 



The weight of the nest (3.5 ounces with the surface dry) bowed the 

 twig so as to bring it within 4 or 5 feet of the ground. 



T]ie nest consists of a large, somewhat irregular mass, with large, 

 low, broadly rounded humps. It is constructed chiefly of coarsely 

 sand}^ clay. On the surface are embedded a few large quartz grains 

 up to 2.5 mm in diameter. In one place there is a rounded patch or 

 overlay about 10 nun in diameter of finer and lighter-colored clay. 

 The length in the direction of the supporting twig is 60 mm; the 

 greatest diameter, at right angles to the length, is 60 mm; and the 

 least diameter is 55 mm. 



There are 21 included cells. These are kidney-shaped, with the 

 concave side toward the twig, 12 to 15 mm long and 7 to 9 mm high 

 in the middle. They are somewhat broader than high. In transverse 

 section the floor, always toward the twig, is seen to be straight, the 

 sides and top strongl}'^ and evenly arched. The partitions between 

 the cells are 3 to 5 mm thick in the thinnest place. 



The first cell is placed in the fork with the long axis at right angles 

 to the plane of the diverging branchlets and the sides almost touch- 

 ing them. The concave side, or floor, is toward the fork and 10 mm 

 distant from it. The second and third cells are on either side of the 

 fork, on the outer side of the diverging branchlets. The other cells 

 are arranged concentrically about the fork as a center, all evenly 

 spaced from one another, the long axes running in any direction. 



The nest was brought to us in the middle of October and was kept 

 indoors during the winter. It probably was not exposed to a tem- 

 perature of less than 65° F. during that time. It was placed in a 

 cloth-covered glass jar with about an inch of saturated newspaper 

 in the bottom, and the surface was thorouglily soaked under the tap 

 once or twice a week. 



This soaking of the surface had the effect of washing out the col- 

 loidal material, so that by the time the wasps were ready to emerge 

 the surface had become very friable, fine sand falling from it at the 

 slightest touch or jar. The effect of this would be greatly to facili- 

 tate the emergence of the insects. 



A thorough search was made for the remains of the insects with 

 which the cells had been stored, but no trace of any was found. 



The cocoon, formed of a rather sparse layer of silk supporting a 

 continuous sheet of gummy substance, is thin and delicate. 



Emergences. — Two males, March 4; two males, March 5; the 

 emergence of the males occurred before 9 a. m., except in one case in 

 which the emergence was not completed until shortly after that time. 



One female, March 15 ; one female, March 17 ; on March 18 the nest, 

 which had become very dry, was thoroughly wetted about 10 a. m., 

 and within 15 minutes a female emerged; one female, March 19; one 



