June, ’23 
JONES AND BRADLEY: LOUISIANA HORSEFLIES 
309 
two have been considered synonymous by some workers. Hine has 
recorded the latter species from Louisiana. Our observations indicate 
that the adults of Tabanus flavus, T. uniformis, and T. turbidus differ 
in their habits from the other horseflies that we have taken in that they 
are crepuscular. Adult females of Tabanus flavus , have been observed 
only during the afternoon of a cloudy day and at dusk. They have been 
collected from cows and horses; being taken at Magnolia (May 12), 
Mound (June 29), and Baton Rouge (Aug. 1). At Mound they were 
common on cows at 7:10 P. M., when ten individuals were counted 
while feeding on the side of one animal. Adults of Tabanus aequalis 
were common on horses in woods at Mound on June 29, 1922, between 
7:10 and 7:55 P. M. 
Females of Tabanus turbidus have also been observed only on the 
afternoon of a cloudy day and at dusk, though it is thought that we heard 
them in flight at about sunrise. Several specimens were taken at 
Magnolia (May 15) while circling about the collectors between 6:00 and 
7:10 P. M. in woods. Although we were in the woods for some time before 
and after this period no adults were heard in flight at these times. At 
Mound a single individual was taken on the afternoon of a cloudy day 
(June 29) about a horse and a number of females were attracted to this 
animal at the edge of, and in, woods in this same locality between 7:10 
and 7:55 P. M. (June 30). 
Notes on Immature Stages 
It is interesting to note that we have not as yet found larvae of those 
horseflies that, as adults, we have noted to be the more common species. 
Our search for larvae has been largely confined to those locations in the 
neighborhood of Baton Rouge where, as in water and in soil close to 
water, the majority of the immature stages taken by other workers 
have been found. This would perhaps indicate that more attention 
should be given to drier areas in searching for the immature stages. 
Numerous larvae of the black horsefly, Tabanus atratus Fabr., the 
immature stages of which are well known, have been taken in wet soil 
and the larvae of seven other species have been taken from such material 
and reared to the adult stage in a well ventilated insectary. In all of 
our rearing work with these species we have kept the larvae in moist sand 
in small glass jars and fed them on earthworms. This method, while 
rather tedious, has proven satisfactory. The size of earthworms given 
as food has been varied with the size of the tabanid larva and it has been 
found that the amount of feeding that a larva will do depends upon its 
