52 BULLETIN 1369, U. S. DEPARTMENT OF AGRICULTURE 4 
pointing in various directions. Some of those closest to the gullet 
entrance were headed toward it. A number were along the line ; 
of attachment of the first and second stomachs. On the surface 9 
of the second stomach a single larva, 7 millimeters long, was found. 9 
On the surface of the colon, about 15 inches from the anus, one larva, 
7 millimeters long, was taken headed forward. Seven larve were 
taken in various places in the mesentery of the small intestines. Six 
of these were 7 millimeters and the other 6.8 millimeters long. One 
larva, 6.1 millimeters long, was found on the surface of the sixth © 
rib, just under the pleura, about half way between the sternum and 
the vertebra. This larva was headed ventrally and was rather 
slender. One larva, 6 millimeters long, was found free on the basal — 
portion of the twelfth rib after the muscular tissue had been stripped | 
off. A careful examination of the other internal organs, diaphragm, 
muscular tissues of the back, and muscles of the legs was made with- 
out finding any indication of the presence of larve. 
It is noteworthy that the larve in the gullet averaged smaller | 
than those in the paunch or elsewhere in the abdomen. This of itself | 
might suggest that the older larve were passing backward from the 
gullet to the paunch or elsewhere. When consideration is given to 
the fact that larve much larger than these are found in considerable © 
PhAarynx 
End 
Fig. 25.—Hypoderma lineatum: Diagram showing position and direction of travel 
of larve in gullet of calf (No. 409) : A, pleural side; B, mucous side 
numbers in the gullet during the latter part of summer and through- 
out the fall, however, the drawing of such a conclusion is hardly 
justified. 2 
Another experimental calf (No. 409, fig. 25) which was infested 
with about 268 eggs on the abdomen and hind legs on March 10 
and 16 was slaughtered on July 9. A cursory examination of the 
viscera, walls of the diaphragm, chest, and abdominal cavities failed 
to reveal any larve. On the gullet, however, in the submucous 
tissue 60 larve were found and on the muscle side of the gullet 16 
larvee were taken in the stroma beneath the pleura. These larvee 
ranged in length from 5 to 5.6 millimeters, but only a few were 
carefully measured. The length of those on the pleural side of the 
eullet was practically the same as those on the mucous side. Of those 
in the submucous tissue 17 were pointing toward the stomach, 40 
toward the pharynx, and 2 were not noted. On the pleural side 9 
were pointed toward the stomach and 7 toward the pharynx. The 
diagram (fig. 25) shows the distribution and the direction of point- 
ing .of these larve. 
The exact course followed by the larve in passing from the body 
cavities to the back has not been determined with accuracy, though 
the presence of larve followed by greenish and gelatinous streaks 
indicates the lines of migration and the probable routes. The find- 
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