26 



MISCELLANEOUS PAPERS. 



They move from one place to another, stopping now and then to sip 

 up any small amount of liquid that the}^ tind, and if one watches 

 closely he ma}- see this liquid disappear from small depressions where 

 they have introduced their sucking mouth parts. I have examined 

 many specimens of both males and females and found their alimentary 

 tracts filled with a liquid slightly yellowish in coloration, indicating 

 that it contained something besides clear water. In Summit County, 

 Ohio, some cucumber trees {Magnolia acuminata) were found to be 

 thoroughl}' infested with a species of scale of the genus Eulecanium. 

 Male and female flies visited these trees in numbers and fed on the 

 honeydew excreted b}^ the scale insects. 



A numl)er of species of the family Tabanidge, aside from the one 

 under consideration, have been observed feeding on the excretions of 

 insects. At Sandusky, Ohio, within a few minutes I took the sexes of 



no less than six species of the genera 

 Chrysops and Tabanus feeding on honev- 

 dew from an aphis, which was abundant 

 on Phragmites, a large species of aquatic 

 grass. 



The various species of Tabanida? have 

 a great many natural enemies and suJ- 

 eifrons is no exception in this regard. 

 Aside from certain species of birds which 

 are known to devour the flies occasion- 

 ally, I have observed that the common 

 bald-faced hornet ( Vespa maculata L., 

 fig. 3) is very active in capturing both 

 sexes, either for food for itself or for its 

 3''oimg. Around the cucumber trees 

 mentioned above the flies were abund- 

 ant, and while located under one of 

 these one afternoon I saw something come tumbling down through 

 the branches to the ground. When in position to see what it was, 1 

 found it to be a horsefly which was being held by a hornet. The matter 

 was interesting, and I watched to see what transpired. The fly was 

 too heavy for the hornet to carry, but the latter, equal to the occasion, 

 immediately began to dismember the former, cutting oft' such parts as 

 were not wanted. With its scissor-like mandibles, and otherwise well 

 prepared for what was to follow, the hornet soon got into position 

 and first clipped the slender neck of its victim, thus separating the 

 head from the rest of the body. Legs and wings came next in order, 

 and finally the a))domen; so that nothing was retained but the thorax. 

 After lacerating this somewhat -and disposing of some of the outer 

 chitinous covering, it rolled the remainder into a sort of a ball and 

 flew away with it — I suppose to its nest. 



Fig. 3. — Vespa maculata, enlarged 

 (original). 



