24 BULLBT] . PI7E8T0 BIOO EXPERIMENT STATION 
from hemorrhage and infection, Attacks from screw-worm flies 
may occur at any time of the year but arc more frequent after the 
end of the rainy season. 
The best treatment for an infested wound is to pour in benzol or 
chloroform, later remove the maggots, and apply pine-tar <»il to 
prevent fresh attack-. The Bureau of Entomology, United States 
Department of Agriculture, recommends the use 01 ! ommercial pine- 
tar oil with a specific gravity of L.065to L.085. Probing and opening 
the burrows arc regarded as inadvisable. All fresh wound- should 
be coated with pine-tar oil to prevent fly blow. The navel of ca 
at time of birth as well as the vulva of fresh cows having a retained 
afterbirth should be protected from attack. 
The maggots of other blowflies may infest the wounds of animal-. 
There arc several- species of these flies in Puerto Rie<» but they are 
of minor importance. The maggots arc usually Located only in old 
: iiiL r wounds or the young are deposited after a -ore has been 
infested with screw worms. Tin- control is the same a- for the - 
worm-. 
Large tail louse of cattle. — The sucking louse ( // 
tubercvla&us) (fig. 2, H) is found in colonies in the switch of the 
tail. On the continent this louse is called the buffalo louse. It is 
found on the American bison. It is bluish gray in color and large 
in size in comparison with other lice. The hairs of the switch of 
the tail may be lined with the nits or ova. Occasionally the 
are found attached to the hairs on the inside edge of the 
Heavy infestations are found especially in dairy cows and calves 
that are confined in stables and corrals. This louse is very common 
on cattle of the southern coast. If the lice are numerous they 
abstract considerable blood and lymph from the host and 
itching and irritation and the formation of abrasions and sores. 
The official arsenical solutions used for cattle ticks are very effec- 
tive for eradicating lice. If cattle are sprayed, the switch and end 
of the tail should be immersed in the solution for a minute or two, 
as spraying is not as effective in control as dipping. Several dairy- 
men have reported that this louse can be controlled by using the 
kerosene-pyrethrum extract sprays. To eradicate lice it is usually 
necessary to dip or spray at Least twice, with an interval of IT to 16 
days between applications, since these preparations cannot be de- 
pended upon to kill the eggs. After treatment the stables and pens 
should be cleaned and disinfected with strong solutions of coal-tar 
preparations. 
Short-nosed ox Iou.<e. — A -mailer sucking louse. II. < wrysU i 
is sometimes found on imported cattle and heavy infestations are 
found occasionally on native cattle. This louse is located on the 
body. Colonies of the lice may be found on the eyelids. 
The stable fly. — The stable fly {Stomoxys ccHcitrans) (fi°;. 2, K) 
is a bloodsucking fly that readily attacks horses and mules, but is 
also common on cattle. This fly resembles the common house fly, 
but, among other differences, it has a long slender proboscis, pro 
big down and forward from the head. The fly deposits its egg- in 
damp fermenting collections of grass, in cane trash, and in hoi - 
cow manure that contains considerable straw. In the dry area- this 
