WASPS EUMENIDAE 77 



avail themselves of this shelter, so that a curious colony is formed, 

 consisting of the Odynerus in its pot, of masses of the young- 

 spiders, and of the little molluscs. 



Home has recorded that the East Indian 0. 2mncttim is fond 

 of availing itself of holes in door-posts where large screws have 

 been ; after the hole has been filled" with provisions, the orifice 

 is covered over level with the surface of the wood so that it 

 eludes human observation. It is nevertheless discovered by an 

 Ichneumon-fly which pierces the covering with its ovipositor and 

 deposits an egg within. 



The genus AUspa is peculiar to Australia and includes some 

 very fine solitary wasps, having somewhat the appearance of very 

 large Odynerus : these Insects construct a beautiful nest with a 

 projecting funnel-shaped entrance, and of so large a size that it 

 might pass for the habitation of a colony of social wasps ; it 

 appears, however, that this large nest is really formed by a single 

 female. 



The species of the genus Rhygcliium are also of insecticide 

 habits, and appear to prefer the stenis of pithy plants as the 

 nidus for the development of the generation that is to follow 

 them. Lichtenstein says that a female of the European It. 

 oculatum forms fifteen to twenty cells in such a situation, and 

 destroys 150 to 200 caterpillars, and he suggests that, as it is 

 easy to encourage these wasps to nest in a suitable spot, we should 

 utilise them to free our gardens from caterpillars, as we do cats 

 to' clear the mice from our apartments. 



The East Indian R. carnaticum seems to have very similar 

 habits to its European congener, adapting for its use the hollow 

 stems of bamboos. Home has recorded a case in which a female 

 of this species took possession of a stem in which a bee, Megachile 

 lanata, had already constructed two cells ; it first formed a parti- 

 tion of mud over the spot occupied by the bee, this partition being 

 similar to that which it makes use of for separating the spaces 

 intended for its own young. This species stores caterpillars for 

 the benefit of its larvae, and this is also the case with another 

 Eastern species, R. nitidulum. This latter Insect, however, does 

 not nidificate in the stems of plants, but constructs clay cells 

 similar to those of Uumenes, and fixes them firmly to wood. 

 Rhygchium hrunneum is said by Sir Eichard Owen to obliterate 

 hieroglyphic inscriptions in Egypt by its habit of building mud 



