THE SOLITARY WASPS 25 



in most inconvenient places, such as keyholes, 

 etc. Some of the solitary wasps have a very 

 curious habit of making a tubular entrance to 

 their hole. These may sometimes be seen 

 projecting from sandy banks. The tube is 

 composed of a series of little pellets of mud? 

 which the wasp by degrees, with the help of 

 its mouth secretions, sticks together till a sort of 

 openwork curved tube of sometimes an inch long is 

 formed (fig. 5). This curve is directed downwards, 



FIG. 5. 



so that the wasp has to creep up it before 

 reaching the actual orifice of the nest. It looks 

 as if the first shower of rain would wash the 

 whole structure away, and I have very little 

 doubt that it often does so. The object of 

 these tubes is difficult to appreciate. There is 

 a bee on the continent which makes straight 

 chimneys above its holes, so as to raise 

 the entrance above the surrounding herbage; 

 possibly these solitary wasps once required 



