59 



make in the sand, and they store the burrows with insects for the 

 young to feed upon when they hatch. It is not unconuuon to find from 

 half a dozen to a dozen specimens of Tabanus in a single burrow, 

 besides other insects. Professor Morgan sa3^s that he has taken sev- 

 enteen horseflies, one Syrphid, one Tachinid and one Stratiomyiid 

 from a single burrow. 



Crahro lO-macuhttus Say, another wasp, is an expert at catching 

 Tabanids, and the writer often saw them capture the flies and carry 

 them away. None of their nests was found, but it would appeal- that 

 they have about the same habit in this regard as the Bembecids. 



Erax maculatns Macq. and species of Deromyia were rather com- 

 mon and were often observed feeding upon difierent species of 

 Tabanidfe. 



That chickens may become a factor in destro3dng- stock pests was 

 proved by the fact that the}" were often observed following cattle in 

 the pasture, picking ofl' such Tabanids as alightedon the lower extrem- 

 ities of the animals for the purpose of sucking blood. 



METHODS OF CONTROL. 



In my "Ta))anidfe of Ohio" I suggested the use of kerosene on the 

 surface of the water for killing larvje hatched from eggs deposited 

 over water. Of course this method could not ])e used in cases where 

 deposition took place over damp ground, as was observed at Cameron. 

 One finds eggs of eosttilis and a number of other species in such places 

 quite frequently. 



With so much standing water to be considered, it would l)e an 

 immense undertaking to use kerosene for killing adult flies, as sug- 

 gested by Porchinski in Russia, and commented on by Doctor Howard 

 in Bulletin No. 20 (n. s.). Division of Entomology (p. 24). It appears 

 that both of the above suggestions, as well as others that might be 

 mentioned, are of most value in special cases; in fact there.is seklom 

 a single remed}'^ in use in economic treatment of insects that is appro- 

 priate at all times with reference to a particuhir species or group of 

 nearly related species. 



It is my belief that species of the genus Tal)amis have a habit which 

 if better understood might be utilized in trapping them in numbers 

 sufficient to materiall}' lessen their ravages. I refer to their habit of 

 collecting in certain places, as on buildings, fences, and the like. The 

 habit has been olrserved at dift'erent times and in difl'erent places but 

 I saw it more forcibly at the Gulf Biologic Station than at any other 

 place I have observed. The sexes of the last three species of Tabanus 

 mentioned above flew around the station building in numbers, often 

 resting on the siding and windows or striking against the glass and 

 screens; then flew away so rapidly that the eye could not follow them. 

 August 23, I obtained permission to open the screens from one of the 



