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THE CA. CATTLE GRUFR Ox WARBLES | 2 
tive tract, thence migrating up to the subcutaneous tissues of the 
back. In 1889 one of these early-stage larvee found in the brain of ° 
a horse by Poulson was described by Boas (5) as a first-stage Hy- 
pederma larva. From this time on the veterinarians, especially 
of Denmark and Germany, made important contributions regard- 
ing the voung stages within the bodies of cattle. 
During the decade beginning in 1884, the English entomologist 
Ormerod made a number of contributions to the literature of this 
subject culminating in reports published in 1894 (77) and.1900 (72). 
In these articles much valuable information is presented, especially 
as regards losses. This writer entertained the old idea that the 
larvee penetrate through the skin of the backs of the cattle. 
In America, interest in this pest began to be evident during the 
eighties; and articles were contributed by Riley (52, 53) in 1889. 
In 1890 Cooper Curtice published a note (24) reporting the finding 
of larvee 10 to 15 millimeters long in the walls of the esophagus, in 
the pleura near the eleventh rib, in the subcutaneous tissues of the 
back, and in subcutaneous tumors which opened through the external 
skin. He states that the finding of larvee in the early stages in these 
situations suggests that-— 
It is possible that the eggs or young larve are licked by the cattle from the 
back; that the larve made their way into the esophageal walls and from 
thence, during the proper season, through the back in the neighborhood of the 
eleventh rib, to the skin. 
Curtice gives in 1891 (25) a full account of his work along this 
line. This hypothesis was based upon the finding of these immature 
stages in the submucous membranes of the gullet and in other tissues 
of the body, often months before the larve appeared on the back and 
eut holes through the skin. He also observed that the larve and 
inflammation disappeared from the gullet by the end of January or 
early in February. Apparently no observations were made on the 
actual habit of oviposition of the flies. In 1892 Riley (84) published 
a very good résumé of the knowledge of the life history and habits 
of H. lineatum up to that date. He concluded from an examination 
of material from various sources that H. lineatwm was the predomi- 
nant if not the only species found in the United States. In this 
article he also incorporated an account, based on observations of 
G. Schaupp and others, regarding the actual method of oviposition 
of this species, and the true first stage was described for the first 
time. e accepts Curtice’s theory of the entrance via the mouth, 
and eoncludes that an additional link in the chain of circumstantial 
evidence pointing toward this method of ingress is supplied by the 
_ fact that the eggs are laid largely on the legs and that the cattle lick 
themselves in that region. In 1897 Marlatt (64) presented a concise 
summary of the information available at that time. 
Horne, working largely on the immature stages within the bodies 
of cattle, published in Norway in 1894 (45) observations showing 
that the larve are truly migratory. He observed them in various 
situations, including the spinal column from one end to the other, 
sometimes under the pleura, in the abdominal cavity, and on the 
surface of the kidney. The following year the veterinarian Ruser 
(86) published his observations on the occurrence of the larve in 
the spinal canal and reported that he had found traces of larval 
tracks in the muscles of the back. In 1898 Koorevaar (54), working 
