THE BIOLOGY OF THE MUD-DAUBING WASPS 43 



the hostess Sceliphron or Chalybion who, when reinforcing her 

 nest with layer after layer of mud on the outside, covers the 

 little foreign cell as well and quite obliterates any traces of 

 its presence. 



Hartman (Bull. Univ., Texas, No. 65, p. 48-49, 1905) calls 

 mellipes a blue insect and describes its habits of nest building. 

 Since Dr. Hartman 's mellipes differed in color and in habits 

 from the mellipes which came from the mud nests of Pelopoeus, 

 I again submitted the specimens to Mr. S. A. Rohwer for veri- 

 fication, and he writes: "I have looked over these specimens 

 again and am sure that my determination of them is correct. 

 In most cases Ashmead made the determinations for Mr. Hart- 

 man and in many cases Ashmead 's determinations cannot be 

 relied upon. We had in the collection of the Museum after 

 it had been arranged by Ashmead three species under the name 

 mellipes." 



Among other insects which occupy the old mud cells are 

 two wasps belonging to the Eumenidae. From the Kansas 

 material of 1912 several specimens of Ancistrocerus (Stenacistro- 

 cerus) fulvipes Sauss, 17 emerged, and in a lot of material from 

 Meramec Highlands in 1911 many A . camestr is Sauss. 17 appeared. 

 These wasps use the old cells without modification, filling them with 

 caterpillars for their young and then resealing them with mud. 



Spiders are often found occupying the old cells, buried deep in 

 a mass of soft web. Often too the larva of the dark meal-worm 

 Tenebrio obscuris, is there feeding on the rubbish that remains 

 after the wasp has emerged. Cockroach egg-cases are some- 

 times found in the cells, and often the pupa of the hairy cater- 

 pillar (Apatela, possibly radcliffei) 18 is found all nestled down 

 in the mass of its own hairs, with the opening of the cell well 

 sealed with the same material. 



THE CONTENTS OF THE NESTS 

 THE KANSAS WINTER BROOD OF 1912 



In May, 1912, in an effort to obtain a supply of material 

 for variation studies I shipped to St. Louis from Lake View, 

 Kansas, about 650 of the mud nests of Sceliphron caementarium 

 and Chalybi on caeruleum. All of the nests were gathered in 



17 Identified by Mr. S. A. Rohwer. 



18 Identified by Dr. H. G. Dyar. 



