7 
The beetles in question are those which habitually live in cattle dung 
and feed upon living maggots therein, or are of the tumblebug 
variety which disintegrate the dung shortly after deposition, thus 
preventing or checking the breeding of the flies. 
The true parasites reared from material sent by Mr. Koebele from 
Arizona proved to be Eucolia impatiens Say, styled ‘‘the Arizona 
dung-fly parasite,” and a species of Eutrias, styled ‘‘the lesser dung- 
fly parasite.” These two minute four-winged flies are undoubtedly 
normally enemies of native dung-breeding flies, but take readily to 
the horn fly. They were reared in considerable numbers and dis- 
tributed among the ranchmen on the islands. It is too early yet to 
determine whether these importations will be of much practical value 
in controlling the horn fly. 
Two other similar minute Hymenopterous parasites, belonging to 
the genus Spalangia, were reared by Mr. Kotinsky from pup of the 
common stable fly (Stomorys calcitrans 1..), from material collected 
on the Island of Hawaii. One of these, Spalangia hirta Haliday, 
confined with horn-fly pup, promptly attacked the latter, and in 
three or four weeks a brood of these parasites was successfully reared. 
Later, horn-fly pupz collected in the field were found parasitized by 
this species. The other parasite, S. lanaiensis Ashm., supposed to 
be a native species, was also again reared from Dipterous pupe. 
That both of these will become important enemies of the horn fly 
seems to be established. 
MEANS OF CONTROL. 
The simple means of prevention of abundance of the flies by the 
destruction of larve in the dung and the protection of animals from 
the attacks of the adults, suggested in the earlier investigation of the 
subject by this Bureau, have remained the standard means of control, 
with some improvements and amplification enabling them to be 
carried out on a larger scale and at less cost. There are two principal 
methods of control—one, the destruction of the larve and pup in 
the cattle dung by direct measures or by the action of natural enemies 
already discussed; and the other, the protection of cattle either by 
the use of repellent ointments or by the actual capture and destruc- 
tion of the adult flies. 
Repellents —Almost any greasy substance will keep the flies away 
for from a few hours to several days. A great many oils and fats 
have been experimented with, and the commercial product known as 
fish or train oil, first suggested, remains the best easily available oint- 
ment. The protection by the use of this mixture varies in different 
regions. In the dry, hot area of the West and Southwest protection 
lasts only two or three days; in the more moist and cooler regions of the 
[Cir. 115] 
