64 BULLETIN 1369, U. §. DEPARTMENT OF AGRICULTURE 
the shoulders, that is, above the scapulas or behind the hip bones, 
the percentage occurring in these regions is comparatively small, 
the writers figures indicating slightly less than 1 per cent for the 
latter. Occasionally grubs are met with on the tail 3 or 4 inches 
below its base, and also on the neck some inches in front of the 
shoulders. One instance of the occurrence of a grub below the 
point of the pin bone has been observed by the writers. Laterally 
most of the grubs are confined to a strip about 1 foot on each side 
of the backbone in grown animals, but it is not especially unusual 
to find them on the ribs half way Gown the side of the animal. The 
‘midline of the back is comparatively free (fig. 30). 
The writers’ experiments show that there is no relation between 
the distribution of the eggs on the host and that of the late stages 
Fic. 30.—Cow with back infested with cattle grubs. Hair is clipped from around 
holes 
of the larve resulting therefrom. As the larve are known to 
migrate freely all through the host, such a relationship would not 
be expected. : 
PUPATION AND DURATION OF THE PUPAL STAGE OF HYPODERMA LINEATUM 
When the larve have freed themselves from the hole in the skin 
in the back of the host they begin contracting and expanding and 
soon roll off on the ground... For the collection of larve as they 
emerged from the hosts, burlap bands were placed around the bodies 
of cattle, as shown in Figure 31. They are not very active.and their 
progress in crawling is very slow. There is a tendency for the larve 
to crawl under any loose objects which may be at hand and which 
would offer some protection; but ordinarily they do not go more 
than a short distance from the place where they drop, and their 
