HABITS AND LIFE HISTORIES OF TABANID^. 27 



After one example of this kind had been observed, watch was made 

 for others, and it was found that the occurrence was common. The 

 hornets could be heard buzzing- in all parts of the tree, and when one 

 had the opportunity it pounced upon a fly and, holding- on with its 

 feet, came down with its prey to the ground, both insects making an 

 abundance of noise with their wings. 



August 6 under a single tree I saw the hornets kill three males and 

 a female of the tabanid within the space of half an hour. At other 

 times during succeeding days the occurrence was watched until it was 

 proven that the habit is a natural one for this particular species of 

 hornet. 



Some variations in the actions of the hymenopteron were noted. In 

 some cases, after cutting off the head and some of the appendages of 

 the fly, it flew to one of the lower branches of the tree with the 

 remains and finished the trimming while clinging to a twig by one 

 hind leg and using the other legs to hold and manipulate its victim. 



The possibility that the hornet stung its prey, when it first pounced 

 upon it, was considered, and although there was no definite way of 

 proving- that such is not the fact, results of observation do not seem to 

 indicate such a procedure. In one or two instances observed the pair 

 came down into the water of a brook that flowed beneath the tree. 

 Under these conditions the hornet became confused and released its 

 hold on the fly, the latter flying awa}^ apparently unharmed. 



Various species of spiders occasionally catch flies of this species, 

 -either by netting them in their webs or by jumping upon them from 

 concealment. 



The use of insecticides against adult horseflies has been more or less 

 unsatisfactory, and whatever good has been accomplished has come 

 almost entirelj^ as a result of using some substance that acted as a 

 repellent to the flies; for thej' are so retiring in their habits that as 

 soon as anyone approaches with a sprayer an animal they are troubling, 

 they are apt to leave and consequent!}' do not usuall}^ receive a direct 

 application. Effort on the part of different investigators to bring out 

 an effective repellent has resulted in the testing of many substances 

 which have penetrating odors. 1 have used a mixture prepared in the 

 proportion of 1 pint of carbolic acid and 1 quart of pine tar to 3 gallons 

 of kerosene. Application was made with a hand spra3"er or atomizer, 

 with the view of testing its effects on the adults of Tahanus s;ulcifro7is. 

 It was satisfactorily demonstrated that the mixture has properties as 

 a repellent, but of such short duration that it could hardly receive 

 practical consideration. When specimens were given a direct applica- 

 tion they were readily afl'ected and as a first result flew awa}- a short 

 distance and then dropped to the ground. 



I have spent nnich time in an endeavor to work out the life his- 

 ioYj of this species, but ui}' efforts have not been fully rewarded. 



