372 The Lung Parasites of Cattle and Sheep, 
them in their order of development, it appears that from the 
instant they are subjected to the new and natural conditions 
Fig. 9. — Larva ofStrongyle under- Fig. 10. — Free Larva of Stron- 
going Metamorphosis. Memoved gyle removed from the Frond 
from the Surface of a Fern- of a Fern Leaf. Length 5^ 
frond. Length of an inch. of an inch. Two days old. 
One day old. 
they proceed to undergo a change of skin (Fig. 9). Although I 
did not observe any previous ecdysis, I think that the process of 
