52 Psyche [April 



mud between the mandibles and adding further material con- 

 centrically within until only a minute opening remains. This 

 she plugs with a small bit of mud and then apparently smooths 

 out the surface of the whole. In the nest of wasp No. 2 a vacant 

 space about 10 mm., long was left between the outermost oc- 

 cupied cell and the entrance. ^ The closure was flush with the 

 surface of the entrance block; it was a plug of cement twice as 

 thick as the partitions within and not smoothed off outwardly. 



The nest of wasp No. 3 was made in a tube which differed 

 slightly from that shown in the figure (Fig. 1) in that the outer 

 end of the tube was flush with the entrance, there being no en- 

 trance block. In this nest the outermost cell reached the entrance 

 of the nest, no empty space having been left by the wasp as in 

 the former case. The glass tube had an inner diameter of only 5 

 mm. The wasp had adapted her construction to this smaller 

 diameter by making the cells longer. The comparative lengths 

 of the cells in this nest and the number of caterpillars provided in 

 each were as follows: cell No. 1,-17 mm., 6 caterpillars; No. 2,-17 

 mm., 7 caterpillars; No. 3,-11 mm., 3 caterpillars; No. 4,-5.5 

 mm., 3 caterpillars. The caterpillars appeared to be of two 

 species and perhaps represented two families (Pyralidse and Tor- 

 tricidae?). 



The following tabulation gives the life histories of the wasps 

 in nests 2 and 3. 



Nest No. 2. 



Cell No. 2 Cell No. 3 Cell No. 4 



& & & 



June 14(?) June 14(?) June 15(?) 

 June 17 June 17 June 18(?) 

 June 23 June 23 June 23 

 June 29(?) June 29(?) June 30 

 July 9(?) July 9 (?) July 10(?) 

 Julv 11 July 11 Julv 11 

 July 19 Oct. 15** Aug. 17 

 *This wasp curiously spun no cocoon, only a few loose 

 threads. It became inactive June 25. 



**Death of this male may have been hastened by falling 

 into the sirup, supplied as food. 



SAccording to Roubaud (1916) such empty cells are evidently for the purpose of confusing 

 parasites. 



