222 DISEASES OF INSECTS. 
glass, after some days he examined it again ; when he 
observed that it had spun the outline of a vertical web, 
had stretched threads from the top to the bottom of the 
glass and from one side to the other, and had also spun 
the radii that meet in the centre, and this was all ; — but 
what was remarkable, the larva that had fed upon it was 
suspended in the centre of this web, where it was en- 
gaged in spinning its own cocoon, while the spider, ex- 
hausted by this last effort, had fallen dead to the bottom 
of the glass. It cannot be asserted positively that this 
suspension of the larva of the Ichneumon in the centre 
of the web always takes place ; but if it does, as seems 
most probable, it shows that this little parasite is en- 
dowed with an instinct which causes it so to act upon 
the spider as may induce it to spin a web so nicely timed 
as to be sufficiently complete at the period of its death 
and of the change of the Ichneumon, for the latter to 
cast it down and assume its station a . 
But the great bulk of the parasitic Hymenopterous de- 
vourers of larvae have their assigned station within the 
body. As Entomologists in breeding insects have paid 
their principal attention to Lejridopteraf it necessarily 
follows that their Ichneumon infesters must be most 
generally known ; but doubtless the larvae of the other 
Orders are not wholly liberated from this scourge: they 
also require to be kept within due limits, and have their 
appropriate parasites. Some, however, in most of them 
have been detected : of which I. shall now proceed to 
state to you the most interesting examples, beginning 
with the Coleoptcra. 
Alysia Manducator x \ remarkable for having mandibular 
" De Gecr ii. 863—. " Panzer Fn. Germ. Init. Ixxii. 4. 
