946 ; Transactions, —Zoology. 
quarters of an inch, containing six cells in a single row; but they are 
seldom found in places from which they ean be easily removed, and are 
so fragile, that, after many attempts, I have only sueceeded in getting one 
nest in anything like good preservation. I have not seen any with the cells 
in pairs. Upon opening a nest, the grub (one in each cell) may be found 
half coiled round the body of a spider which it is devouring. These spiders, 
though apparently lifeless, are not dead. The old nests contain the heads 
and legs of spiders, but in no instance have I met with any other insect in 
them. I can hardly believe that this remarkably fly is indigenous, though 
it may be closely allied to the one that captures small insects promiscuously 
and buries them in the ground, I suppose for the same purpose :— 
“ Last summer, a correspondent at Marton drew attention to a fly which 
attacked, and apparently killed spiders; and another, who seemed to know 
the insect, stated it to be an Ichneumon fly. This year they are not so 
numerous ; but ample opportunities have been afforded for observing their 
habits, and it appears that they have also the character of Mason Bees, or 
Wasps. They construct nests consisting of a double row of cells, each of 
which is about a quarter of an inch in diameter, and half an inch deep. 
These cells are composed of clay, which the fly collects ; and while forming 
them it emits a shrill sound like that of a blowfly entangled in a spider’s 
web. As soon as a couple of cells are completed, the fly crams each of them - 
full of spiders, alive, but apparently paralysed, and along with them, or in 
one of them, deposits an egg, which in a short time becomes a erub, resem- 
bling a bee or wasp grub, that devours the spiders. As the cells are filled, 
they are closed with clay, which forms the bottom of a second pair, and so 
the process goes on till a nest several inches long is formed and stocked with 
its living inmates. The nests are built'against the angles of ceilings, rafters 
of verandahs, and other sheltered places, and a favourite situation seems to 
be the folds of a cloth, or other similar articles. In some houses as many 
as a dozen or more such nests have been destroyed this summer ; and a 
survey-party working a few miles inland, have been quite annoyed by the 
insects, three or four nests per day having been built in the spare garments 
of the party, or in the folds of the bag which held their bedding and pro- 
visions. The fly is of a dark grey colour, almost black, and about the size 
of an ordinary bee, but rather longer and thinner. The walls of the cells 
are about a sixteenth of an inch thick, so that the insect, which, after 
devouring its stock of food, no doubt changes from a grub into a chrysalis, 
and thence into a perfect fly, will have no difficulty in breaking out of its 
prison. The fly is indigenous, but from some cause evidently on the 
increase, and seems quite harmless to anything but spiders.” 
