THE HABITS OF EUMENES BELFRAGEI, CRESS. 1 



CARL HARTMAN 



The University of Texas 



Seven figures 



The present paper is a record of the habits of Eumenes bel- 

 fragei, Cress., one of the mason wasps of the family Eumenidae. 

 The members of the genus Eumenes have long been subjects of 

 interest, chiefly perhaps for esthetic reasons, since this wasp is 

 an expert mason, building a neat nest in the shape of a water 

 bottle on the stems of herbs and shrubs. The nest is symmet- 

 rical and graceful in outline and is provided with a neck and a 

 rim around the mouth. The outer surface is, moreover, deco- 

 rated with "sculpturings." Within this nest the wasp lays an 

 egg and then stores the nest with a score or more of small cater- 

 pillars, after which she plugs up the mouth of the cell and goes 

 away to repeat the performance elsewhere. 



Eumenes is solitary in its habits and in this respect resem- 

 bles the Sphecina or digger-wasps, with which group most sol- 

 itary wasps are classed. On morphological grounds, however, 

 especially because of the plaited wings, Eumenes is allied to 

 the social wasps and is classed with these under the super- 

 family Vespina. A general classification of the stinging wasps 

 on the basis of habit is given in the following outline for the 

 further orientation of the reader. 



I. Vespina 



(True wasps.) " 



' 1. Social wasps (Vespidae) ] a. Mud plugs in ready made 



cavities. 

 ( (E.g., Odynerus, sp.) 

 2. Solitary wasps. (Few dig- f b. Mud nests. 



ging; mostly mud- work- | (E.g., Eumenes, Odynerus, 

 ing: Eumenidae.) J sp.) 



f 1. Digging wasps. (Nests dug 1 a. Mud plugs in ready-made 

 II. Sphecina in the ground.) _ cavit ^. es - , , 



(All snlitarv ^ 1 (E.g., Trypoxylon.) 



tAii solitary.; . 2 Mud . working wasps _ | b Mud nests 



[ J (E.g., Pelopaeus, Agenia.) 



The outline shows that the habit of making mud nests has 

 arisen in different groups of wasps. Indeed the habit of work- 



1 Contribution from the Zoological Laboratory, University of Texas, No. 114. 



353 



