180 Entomology, 



two triangular meshes, one of which is very small, and situated 

 near the middle of the wing, the other mesh larger and near the 

 the base ; the hind body roundish but laterally compressed ; 

 and the piercer spiral or curved, and concealed. The Chalci- 

 dians have shorter, elbowed, and drooping antennae, which are 

 enlarged towards the end ; a single vein, running from the 

 shoulder near the outer margin of the fore-wing, uniting with 

 this margin near the middle, and emitting thence, towards the 

 disc of the wing, a short oblique branch, which is enlarged or 

 forked at the end ; the hind body generally oval, pointed at the 

 end in the females, and provided in this sex with a straight piercer, 

 which is more or less visible beneath, and prominent at the ex. 

 tremity." 



About a month ago, I picked up a specimen of Helix albolabris. 

 Upon examining the shell, I discovered that the animal it con- 

 tained had been consumed, and nothing remained but a number 

 of larvae attached to the interior. I took them to be coleopterous, 

 as they appeared to the naked eye to resemble that of Dermes- 

 tidce — since then they have turned out to be Diptera. The form 

 of antennae classes it as a Tachina, but in general characters it 

 resembles a minute species of parasitic Sarcophaga ; it differs 

 •from Tachina in having its wing longitudinally folded when at 

 rest. This is the first instance within my recollection of having 

 found a dipterous parasite within a terrestrial mollusc. 



I once had the pleasure of witnessing the stratagems of a little 

 cuckoo fly ; it was on the island opposite Toronto, where a large 

 spider is found during summer, generally under stones, and in the 

 sand. Nature has clothed this spider, as is invariably the case 

 with insecta that conceal from their enemies, in colors resembling 

 the sand it inhabits, — however, color does not protect this spider 

 from all its enemies, particularly a sand wasp Sphex Pennsylvanica ; 

 indeed, these spiders constitute the principal food of the larvae of 

 these wasps. I observed one of the wasps running backwards, 

 holding and dragging with its mandibles the body of a spider; it 

 would occasionally drop it and reconnoitre, forming a series of 

 circles, which were extended according to distance from centre, 

 and although these round-about excursions were many times re- 

 peated, the wasp, with head down, like a dog on scent, arrived at 

 the identical spot where its prey lay. Its manoeuvres appeared 

 strange to me ; oft times it stood in an erect position with open 

 mandibles, as if in defence, and well it might, for all this time it 



