June, ’23 
JONES AND BRADLEY: LOUISIANA HORSEFLIES 
311 
Tabanus annulatus was formed in confinement on April 11 and the 
pupal stage of the several individuals under observation average 15 
days, adults issuing for the most part during the first few days of May. 
The larva of Tabanus fulvulus was taken late in January, pupated on 
April 19, and the male adult issued on May 4. 
Notes on Adults 
We have attempted to ascertain, by field observations, the time of 
year when the adults of various tabanids occur in the vicinity of Baton 
Rouge, realizing, however, that this information is not necessarily indic¬ 
ative of conditions in other localities, even in our own State. The follow¬ 
ing table gives data that we have obtained during 1922 for some of our 
most common species. 
Seasonal Occurrence of Adult Tabanids in the Vicinity of Baton Rouge as Indicated by 
Collections Made During 1922 
Species 
Earliest date taken 
Latest date taken 
Period of greatest abundance 
Chrysops callidus 0. S. 
April 11 
June 26 
May 
fiavidus Wied. 
April 27 
Oct. 4 
Summer months 
obsoletus Wied. 
May 16 
Sept. 13 
Summer months 
pikei Whit. 
April 11 
June 26 
May and June 
vittatus Wied. 
April 25 
Sept. 13 
June 
Tabanus abdominalis Fabr. 
June 26 
Oct. 12 
September 
annulatus Say 
May 13 
June 29 
Never common 
atratus Fabr. 
April 25 
Nov. 1 
Never common 
benedictus Whit. 
June 26 
Sept. 20 
Never common 
costalis Wied. 
April 25 
Sept. 13 
April to September 
fulvulus Wied. 
May 7 
May 16 
fuscicostatus Hine. 
May 16 
June 30 
May and June 
lineola Fabr. 
April 25 
Sept. 30 
Summer months 
pumilus Macq. 
April 11 
July 28 
Last week in April and first 
week in May. 
During the spring of 1922 Tabanus pumilus was so abundant as to be 
regarded, as the worst stock pest of all tabanids in the vicinity of Baton 
Rouge, though it must be borne in mind that in other years or in other 
sections of the State this species might not rank as so important a pest. 
The female flies of Tabanus pumilus confine their attack, for the most 
part, to the head of the animal, especially the ears. As a result these 
parts often become swollen and bloody. In one instance, on a mule,, 
the blood from a large number of bites was flowing down the face and 
dripping to the ground. The adults do not hesitate to attack man, in 
which case they also show a preference for the head, especially if a dark 
hat is worn. 
Some writers have already pointed out that certain horseflies are 
sometimes attracted to moving objects, such as trains and automobiles. 
We have noted this fact in connection wfith certain species of Tabanus 
and Chrysops. Adults of Tabanus pumilus and T. fuscicostatus have 
been observed to circle about and alight on an automobile while it was 
being driven over roads through woods. In one instance adults of the 
