24 MISCELLANEOUS PAPERS. 



In Ohio the first specimens of the species usually appear about July 

 20 and specimens have been taken as late as the middle of September, 

 but the period of greatest abundance is the first three weeks of August. 



The adults are most in evidence when the sun is shining most 

 brightly. As evening approaches they become less active and seek a 

 resting place among foliage, on some tree trunk, on a fence or post, 

 or in some similar place, where they remain quiet until the sun 

 appears the following morning. These flies have a tendency to collect 

 in certain favorable places in large numbers at evening, and if the 

 collector or observer finds such a place, a visit to it b}' 7 o'clock in 

 the morning will give an opportunity to procure plenty of specimens 

 of both sexes, or abundance of notes on habits. When the sun has 

 warmed the atmosphere somewhat, the flies begin to run over the 

 objects on which they passed the night, or to fly from one perch to 

 another. Both sexes are plentiful, the males often more plentiful 

 than the females, and there is no diflference in habits that makes it 

 possible to readily distinguish the sexes. Specimens are easily taken, 

 for by using care they may be picked up with the thumb and fingers, 

 or if it is desired to use a net, it is not diflicult to procure large num- 

 bers in a few minutes. 



The only times I have observed copulation in the Tabanidw were in 

 places similar to the one just described and always about 8 o'clock in 

 the morning. In a paper by the writer on the '^ Tabanida of Ohio " " it 

 is recorded (p. S) that on the 18th of August, between 8 o'clock and half 

 past 8, several pairs of T. sideifrons were observed in couple on the 

 fence, and several pairs taken. The male in instances observed clung 

 to the edge of a rail, and the female, with legs and wings motionless 

 and touching nothing, hung suspended. My observations at this time 

 led me to think that the opportunity for studying the mating habits 

 of the species in question, and also of some others of its family, is con- 

 fined to a particular time of da}', and subsequent observations have 

 not made it necessary to alter this opinion. On August 17 of the fol- 

 lowing 3'ear, about the same hour and near the place where the obser- 

 vations mentioned above were made, 1 captured nine pairs of the 

 species, most of which were on the fence. At this time an efi'ort was 

 made to add to the data obtained before. It was then observed that 

 when pairs were disturl)ed sufiiciently to cause them to leave, the male 

 did all the flying and proceeded only a short distance before alighting, 

 either on the ground or on low-growing foliage, or it flew in a curve 

 and soon returned to the fence. Coition in no case observed lasted ■ 

 over ten minutes, and all the pairs were taken within a quarter of an 

 hour, after which time no more could be found. 



As the hour became later fewer and fewer specimens were to be 

 seen, and long before noon nearly all of the flies had left the places 



ffOhio State Academj^ of Science, Special Papers, No. 5, May 1, 1903. 



