320 MB. H. L. ROTH ON THE HABITS OF 



undisturbed, slie goes a step further, and by means of diagonal 

 streaks of mud gives the nest tbe look of a small piece of tbebark 

 of the common European Acacia. When laying on the mud, 

 either at the very commencement or at the end, she works it by 

 placing it on the required spot and then drawing it backwards 

 towards herself, after which she runs to and fro over it, thus 

 giving it the right shape. 



When the spiders are all consumed the larva pours out of its 

 mouth a dark yellow transparent material, which forms a shell 

 around it, and looks much like gold-beaters'-skin ; at the bottom 

 of this shell is a hard black lump, and outside the shell are found 

 the juiceless bodies of the spiders. There is no Lining to the 

 cell. Between this shell and the cell-wall a little fluff is formed, 

 and this keeps the former in its position. 



"When the perfect insect is developed (it is not doubled up in 

 its cell) it breaks through, and after cleaning itself flies away 

 without any preliminary canter. I have not noticed whether on 

 emerging the little drop of liquid is produced. 



These wasps are terribly infested by Dipterous and other para- 

 sites, some of which appear to destroy the larvae indirectly by 

 consuming the prepared food (the spiders). "With the flies the 

 case is somewhat peculiar, as the mother insect appears to follow 

 the wasp when she is carrying a spider, and deposits her egg on 

 the food originally intended for the ofi'spring of the wasp. I once 

 found two and once five (Nov. 14, 1883) cocoons of th ese flies. In 

 course of development the larvse of these flies may be seen thriving 

 on the spiders in the same way as the larvae of the wasp ; but as 

 they devour the juice of the spiders very quickly no food is left 

 for the wasp's larvae, which, being unprepared at that stage to 

 develop into pupae, naturally die, and the mildewed remains of 

 their bodies are found in the cell after their fully developed 

 enemies have quitted it. 



Another parasite appears to commence its attack on the 

 insect itself in one of its more advanced stages. On one 

 occasion I obtained three specimens of this parasite in its 

 pupa-state. I found the pupae inside the above-mentioned 

 gold-beaters'-skin-hke shell, so that the egg must have been de- 

 posited through the mud-wall and shell on to the young wasp 

 either whilst changing from the larval to the pupal state or when 

 it had already been transformed into a pupa. The pupae of 

 these parasites are extremely lively. 



