The Robber Flies. 415 
them pinned, as they were captured, in our college cabinet. 
These flies delight in the warm sunshine, are very quick 
on the wing, and so are not easily captured. It is to be 
Fic, 196. 
hoped that they will not become very numerous. If they 
should, I hardly know how they could be kept from their 
evil work. Frightening them or catching with a net 
might be tried, yet these methods would irritate the 
Fig. 1997. Fic. 199. 
bees,.and need to be tried before they are recommended. 
I have received specimens of this fly from nearly every 
Southern State. During the past summer this same fly 
has been well employed here in Michigan. It has been 
observed to kill the cabbage butterfly by scores. 
