58 



Tahanus lineola Fab. is a widel} T distributed species and everywhere 

 is of especial economic importance. It was common at Cameron, and 

 is one of the three species referred to above as being especially 

 injurious. 



Tahanus costalis Wied., the common greenhead, was abundant and 

 appeared to be more persistent in its attacks than any of the others. 

 When sucking blood it is usually located on the under parts or on the 

 fore legs, where an animal has most difficulty in reaching it, and once 

 it alights it is pretty sure to satisfy its appetite before leaving. 



Tahanus quinquemaculatus Wied. has not been reported from the 

 United States heretofore, but the commonest species observed at 

 Cameron agrees very closely with Wiedemann's description. Besides, 

 it is reported from Mexico by both Wiedemann and Bellardi, so it 

 would not be strange to find it in Louisiana. This species appears 

 much like costalis, but is larger, has two purple bands on the eye 

 instead of one, and the costal cell is hyaline. It is also close tolineola 

 in appearance, but the color of the vestiture of the body is decidedly 

 more yellowish, and the upper purple band of the eye is noticeably 

 narrower than in that species. Besides, it averages larger than either 

 costalis or lineola, but undersized specimens are often met with. 



Since no systematic experiments were carried on at the Gulf Bio- 

 logic Station, what the writer has to say regarding remedies may be 

 considered as suggestions, derived partly from observations on the 

 conditions existing in that section, and partly from work and experi- 

 ence in Ohio. 



NATURAL ENEMIES. 



The natural enemies of the Tabanides is an interesting subject for 

 investigation at the Gulf Biologic Station. The writer is under obli- 

 gations to Messrs. Ashmead and Coquillett for the names of most of 

 the species mentioned below. 



Monedula Carolina Fab., a large and attractive species of the family 

 Bembecida?, is common, and its habit of flying around horses and 

 cattle for the purpose of catching Tabanids and other stock pests is so 

 noticeable that it has received the common name of horse-guard. ° 

 One commonly sees from one to three or four of these at work 

 around a single animal. 



Bemoex helfragei Cr. belongs to the same family as the last and like 

 it is an important enemy of horseflies. It has different habits, how- 

 ever, for instead of capturing prey around animals, it flies about the 

 fields in the vicinity of marshes and captures males and females at 

 their breeding grounds. It is a common occurrence to see a specimen 

 carr} T ing an adult Tabanid. 



Both the above species deposit their eggs in burrows which they 



« A name which it shares with the great digger wasp (Sphecius [Stizus] specioms Drii. ). 



