﻿THE CATTLE GBUBS OR OX WAEBLES 17 



ment 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 {^3), in connection with a discussion 

 of losses ]3roduced 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 larvse 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 larva? 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 larvse 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 larvae penetrate the skin 

 upon hatching. In the experience of Glaser {29, N'o. 5, p. 35) while 

 experimenting with the grub, there is an example of the deposition 

 of an ^gg 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 resume 

 of the case is given. A child O years old, living on a farm, was 

 brought to Doctor Kimble's oflice during the lii-st week in Novem- 

 ber, 1020. She romj>l!iine(| of a swelling of (he left forearm with 



8 Hamilton, John. Medico-entomology. In Ent, Ncwu, vol. 4, pp. 217-211), 1803, 

 58252°— 20 2 



