Dey BULLETIN 1869, U. S. DEPARTMENT OF AGRICULTURE 
2 larvee appeared on the back December 12, also in the lumbar 
region. Each larva had cut a hole through the skin, and from these 
holes there was an extensive discharge of serum which hardened, 
matting the hair over the grub, thus indicating a marked reaction 
on the part of the host against the larve. All evidence of the 
presence of the larvee disappeared in a few days. 
During 1922 H. E. Cross forwarded a series of Hypoderma larvee 
from goats on the Punjab, India. Most of these proved to be ZH. 
crossi Patton, but there were two larve of H. lineatum, one in the 
fourth and one in the fifth stage. 
Peter (76) placed 45 larvee, removed from the spinal canals of cat- 
tle, under the skin of two goats; a single larva finally completed its 
development. 
Koorevaar (54) showed that it is possible for larve of H. bovis 
to complete development in a goat after their removal from the 
spinal canal of cattle and introduction under the skin of the goat. 
Brauer (8) records sheep (Ovis aries) as a host for Hypoderma 
larvee, stating that Winnertz had seen a number of flies following a 
flock and that Schwabs asserted that grubs occur under the skin of 
shorn sheep. These he pronounced to be 7. bovis. It is noteworthy 
that Brauer placed a question after Ovis aries as a host. The writers 
have never observed a larva of Hypoderma on a sheep in nature, nor 
have they seen any indication of the attack of sheep by heel flies. 
The writers have carried out a few experiments to illustrate how 
larvee will develop in sheep. The flies seem averse to laying eggs on 
the wool, but oviposit readily on the hairs of the legs. Forty eggs 
attached by a fly above the hoof of a sheep apparently did not hatch, 
or-at least no lesions indicating penetration were observed. These 
eggs were known to be viable. During the spring of 1922 about 75 
eggs were deposited on the legs of a sheep; subsequent examinations 
failed to indicate that hatching or penetration had taken place. 
Some of the eggs of this lot were known to be fertile. During the 
spring of 1923 at least a few eggs of a number deposited on the leg 
of a sheep hatched and the larve penetrated, as indicated by the 
presence of lesions. 
Two grade Shropshire sheep were infested November 29, 1922, | 
by inserting under the skin a few inches above the right hock 20 | | 
H. lineatum larve averaging 13.2 millimeters in length, taken from 
cattle gullets. These were probably all second-stage larvee when in- 
troduced. On December 7 one larva appeared on the back of one — 
of the sheep, and on December 9 one came up on the other host. e | 
Larvee continued to reach the subdermal tissues of the backs of both | 
sheep at intervals of a few days until January 3, 1923, when a total _ 
of 11 had reached the back of each animal. They were rather gen- | 
erally distributed over the backs, but more numerous in the lumbar ~ 
region. There was more or less exudate from the grub holes, and in ~ 
no case did the larve remain longer than about 10 days before suc- — 
cumbing. Several dead larve, all in the fourth stage, were found at — 
different times in the wool. : 
Many people are of the opinion that Hypoderma larve are to be ~ 
found in small domestic and wild mammals. There are no published | 
records of such. occurrence in nature, and the examination of many 
small mammals in the course of the work leads ig the belief that — 
