364 PROCEEDINGS OF THE NATIONAL MUSEUM. vol. xxxi. 



The prey of Chlorion elegans is reported by Coquillett as being 

 (Ecantlius niveus De Geer. 



Mr. 8. Arthur Johnson, of the Colorado Experiment Station, Fort 

 Collins, (Colorado, has made some observations on the nesting habits of 

 this species and has kindly sent me the following notes on the subject: 



A number of the adults of Chhrion {Isodontia) cleyans have been reared by the 

 writer from cocoons taken from the nests. In all these cases they were taken from 

 the adobe banks where Anthophora occldodalis makes its home. 



In order to make clear the conditions, it should be explained that the latter species 

 nests in vertical adobe liluffs where the material is so hard and dry that it is removed 

 with the knife blade or other tool with great difHculty. The bees nuich prefer a 

 southern exposure; are sometimes content with a west or east front, but seldom 

 select a place which is not exposed to the sunshine at some hour of the day. Into 

 this hard substance the bees burrow to a depth of from 6 to 10 inches, making the 

 diameter about three-eighths of an inch. At the end of the burrow a cluster of urn- 

 shaped cells is made, stored with pollen, and provided with eggs; the cells and the 

 entrance to the burrows are sealed. In order to make way through the hard material, 

 the bee brings water from the neighboring brook and softens the dirt; the waste 

 material is used in part to build a curious tube-like doorway. 



There is reason to believe that Isodontia elegans occupies only the discarded bur- 

 rows of these bees or related species. I have never found the nests in other locations, 

 nor have I found any evidence that the wasps ever dig their own nesting places. On 

 the other hand, the entrance to their homes almost always shows signs of Anthophora' s 

 work, and in instances where I have dug beyond the cocoons of Isodontia I have 

 found the empty cells of the bees at the end of the burrow. 



The nests of /. elegans are made from 2 to 4 inches within the tunnel and are com- 

 posed of finely chewed fibers of dead weeds and grass. The food consists of (Ecanthus 

 sp. or in some cases of nymphs of grasshopi^ers between 5 and 10 millimeters in length. 

 Usually there are two cocoons in the tunnel, l)ut in one case I found four. The 

 outer portion is tightly packed with grass stems of coarser nature than those used 

 for the nest proper. These fibers are wound round and round the burrow and 

 packed in very firmly and securely. The packing extends to the mouth, where it 

 commonly protrudes slightly. Some tubes were packed with closely arranged sprigs 

 of sage. 



The cocoon is composed of fine fibers of silk, and consists of three layers. The 

 outer is a loosely woven mass of silk which often entangles loose materials, legs, and 

 dried parts of the food material, bits of finely chewed grass, etc. Below this is a 

 thin, papery, pinkish layer with a shining surface which appears to be made by 

 gluing the silk together by means of some fluid. This layer is so tight that it doubt- 

 less has much to do with regulating the degree of moisture within. The inner layer 

 is yellowish, quite thick, more loosely woven than the middle layer, but more com- 

 pact than the outer. It fills all the space between the middle layer and the pupa case. 



The length of the old larval exuvia in whii'h pupation takes place is 19 mm., 

 breadth 5i mm., elongated, almost cylindrical in form, but slightly larger at the 

 anterior end. Color, the usual brown of Dipterous larv;e. 



Three species of insects bred from these cocoons, sent mo by Mr. 

 Johnson, have been identified through the kindness of Dr. L. O. 

 Howard, of the Department of Agriculture in Washington, as Argy- 

 7'amcBhafu7' O. S., Senotainia trilineata Van der Wulp, and fPerilam- 

 pus cycmeiis Brulle. Doctor Howard writes: "I think it very doubtful 

 that this (the last-named species) is a parasite of the Isodontia^ but it is 

 likely to be parasitic upon the ArgyrauKjeba.^'' 



