
502 THE INSECT WORLD. 
These larvie devour the snail whose dwelling they occupy, as do 
the larvee of the Lampyris. Mieczinsky saw them emerge, but 
obtained only females, which differed scarcely at all from the 
larvee from which they proceeded. He made a separate genus of 
them, under the denomination of Cochleoctonus, and called the 
species vorax. Later, Desmaret resumed these observations. He 
provided himself, at the Veterinary College of Alfort, with a 
number of shells of the Helix, filled with the same larve. He 
saw come out of them, not only Cochleoctoni, but also Dryli, and he 
watched their coupling. It was then proved, by this unanswerable 
argument, that these two insects, so unlike each other, belong 
to the same species. 
The larva of the Drylus flavescens fixes itself upon the shell 
of the snail by a sort of sucker, like a leech. Little by little, it 
slips in between the mollusc and its house, and devours it entirely. 
To change into a pupa it shuts up the entrance to the shell with 
its old skin, and when arrived at the perfect state, quits the shell 
which served it as a temporary dwelling. The females of the 
Drylus flavescens take refuge under stones and dry leaves, or 
crawl slowly along the ground, whilst the males, which fly with 
great ease, are on the plants and brushwood. These insects are 
not rare in the environs of Paris, M. H. Lucas has observed, 
in Algeria, near to Oran, another curious species, the Drylus 
mauritanicus. The larva of this insect lives at the expense 
of the animal of the Cyclostoma Volzianum, which closes the 
entrance to its shell with a covering of some calcareous sub- 
stance. It fixes itself on the edge of the shell, with the aid 
of its sucker, and directs its strong mandibles to the side on 
which the snail is obliged to raise the covering, either to 
breathe the air or to walk. In this position it has the patience 
to wait for many days at the door. The snail puts off for 
as long a time as he is able the fatal moment. But when, over- 
come by hunger or nearly stifled in his prison, he decides at 
last to open his door, the Drylus profits immediately by this 
opportunity, and cuts the muscle which keeps back the foot of the 
snail. The breach being made, nothing more opposes itself to 
the entrance of the enemy. He slips in, and sets to work to 
eat at his leisure the unfortunate inoffensive mollusc, which affords 

