ENTOMOLOGY

BIOLOGY AND HABITS OF HORSE FLIES l!45for the spread of disease, if there are diseased animals in the herd. Thi~habit of bunching up under fly attack applies also to cattle, where theattack is severe.I have never succeeded in obtaining any data on the number of bloodmeals a female will take. Mitzmain states that in the Philippines femalesof TabM11U8 striatus bite not oftener than once iIi ! days.CONCERNING CONTROL MEASURESNo universal remedy, or control measure, for horse flies can be given,owing to the diverse habits of the different species. In all cases, someknowledge of the life histories and habits of the species involved isnecessary before anyone can intelligently set in motion control measures,and I may say here that the life histories of very few species of Tabanusare now known.In some cases drainage of the larval habitat would undoubtedly bea good control measure. But the degree of drought resistance of thespecies in question should be ascertained before placing reliance uponthis method of control.In Russia a species of Tabanus has the habit, in the adult form, offlying to water and dipping the abdomen. Porchinski, the Russianentomologist, advocates the oiling of the surface of the water as a controlfor this species. It appears that Porchinski has used this methodwith good results. He applied the equivalent of a half pint of kerosene tosix square feet of water surface. If this was not sufficient to do the work,a like amount was used the next morning. It must be borne in mind,however, that not all species of Tabanus have this dipping habit, and thatin order to make the measure effective, the water would have to be comparativelystill, as otherwise the oil would soon pass off with the current.Occasionally the importation of egg parasites may be an effectivecontrol measure. At the present time, Tabanus punctifer in the AntelopeValley, Mono County, California, is apparently largely controlled by anunidentified hymenopterous egg parasite.Hine mentions the fact that in confinement small catfish eat the larvreof Tabanus stygius. It is possible that the stocking with catfish ofstreams inhabited with Tabanus larvre might have good results.In the way of protection of animals from the attacks of adult flies,various devices h""ve been tried, such as nets, hoods, etc. In the SierraNevada Mountains, I found in one locality, a very useful horse hood inuse to ward oft' the attack of Taba'fI/US phaenops. This species attacksmost viciously about the head and neck of horses. The hood is a simplearrangement made of light canvas to slip over the head and neck, witheye and breathing holes at the proper places.