= 
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THE CATTLE GRUBS OR OX WARBLES 1b 
erent of hide dealers and tanners that the discount of 1 cent per 
pound is really too small, we may reasonably place the total loss 
to the hide, tanning, and leather industries of the United States at 
$5,000,000 each year. Coppens (23), in connection with a discussion 
of losses produced by this insect in Europe, states that the War 
Ministry at Brussels found that the wearing properties of grubby 
hides as leather is only 30 per cent of that of sound hides. Mason 
(65) also touches on the importance of grubs to the tanning in- 
dustry. De Vries (27) and Ostertag (74) also discuss losses in 
Europe due to these insects. 
After a careful consideration of the various losses brought about 
by the cattle grubs the writers have concluded that they are con- 
servative in placing the annual loss in the United States chargeable 
to them at $50,000,000. 
INJURY TO MAN 
Many cases are on record in which larve of Hypoderma have 
| been extracted from man. They are found usually in the subdermal 
tissues, where they produce what is often called “creeping myiasis.” 
There seems to be a tendency for the larve to work upward and 
most of them are finally extracted from the head, face, or upper ex- 
tremeties. These migrations are often extensive and rather rapid, 
accompanied by considerable pain. In some cases the larve appear 
under the mucous membranes of the mouth. 
The source of these infestations in man is not known, but most of 
them have been in children and usually the affected individuals have 
been more or less associated with the cattle. It is probable that 
the flies occasionally oviposit on the hair of the heads or legs of 
children or on their clothing and the larve penetrate the skin 
upon hatching. In the experience of Glaser (29, No. 5, p. 35) while 
experimenting with the grub, there is an example of the deposition 
| of an ege on woolen clothing. In this case the resulting larva 
hatched and penetrated the skin of the leg. Some time later its 
| presence in the gastric and esophageal regions was detected by an 
| uncomfortable feeling. The larva apparently passed up the esopha- 
| gus and was later extricated at the base of one of the lower molar 
teeth. 
Hamilton *® records a case of a boy who was suffering for some 
months from swollen glands on the neck, accompanied by a fetid 
ulceration around the back teeth on the lower jaw. After three 
| months of unsuccessful treatment a well developed tawny warble 
larva was discovered in the ulcer at the root of the tongue. The 
case resulted fatally. 
The writers have obtained through W. A. Riley, of the Uni- 
versity of Minnesota, the clinical history, as prepared by O. A. 
Kimble, of a case of dermal myiasis. As this case is typical, and 
as opportunity has been afforded of examining the larva, a résumé 
of the case is given. A child 6 years old, living on a farm, was 
brought to Doctor Kimble’s office during the first week in Novem- 
ber, 1920. She complained of a swelling of the left forearm with 
5 Hamilton, John. Medico-entomology. In Ent, News, vol. 4, pp. 217-219, 1893, 
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