AS BULLETIN 1369, U. S. DEPARTMENT OF AGRICULTURE 
has observed the tracks of the larve up the tendons to the knees or, 
hocks in the elbow and patellar regions and in some cases farther 
up the legs; no larve, however, were recovered in these regions. 
For many years it has been known that larvee of the genus Hypo- 
derma are found in considerable numbers in the connective tissue 
between the mucous lining and the muscular coat of the gullets of 
cattle. Since one of the writers (57) has found a method of deter- 
mining accurately the species of the larve in any stage of their 
development, numerous collections of specimens have been examined 
from the gullets of cattle in regions where H. bovis occurs plenti- 
fully, and only one specimen of ‘that species has been found. These 
observations involved the examination of 1,140 larve removed from 
the gullets of 563 cattle, and during every ‘month of the year when 
they were found to be present in that part of the host. It is safe 
to conclude from these observations that the larvee of this species 
do not have the habit of going to the gullet and spending some time 
Fic. 23.—Cow licking hee! where larve of Hypoderma lineatum are penetrating 
there as occurs with H. lineatum.- The single larva of H. bovis 
found in a gullet was taken at Chester, N. Y., on December 19, 1922. 
It was 10 millimeters long and was found lying loose on the tissue 
at about one-fourth the length of the gullet from the pharynx. 
Since it appears that 7. bovis does not frequent the gullet it may 
be taken for granted that all, or practically all, of the published 
statements of the occurrence of Hypoderma in the gullet appertain 
to H. lineatum, and the following discussion relates to that species 
only: 
The principal data appertaining to the occurrence of the larve 
in the gullets are given in Tables 3 and 4. It will be observed that 
there is a gradual increase in the average size of the larve from 
their first appearance to their migration from the gullet. The range 
in sizes is observed by the writers to be from 1.5 to 16.9 millimeters. 
Among the larve found in the gullet only a small percentage. are 
in the third stage, the others being in the second. Hadwen (40) 
reports finding in the submucosa of the gullet of a heifer a larva 
at least 2 millimeters long which he donedered in the first stage. 
