202 STUDIES IN INSECT LIFE, ETC. 



in other portions of the alimentary canal. As 

 a rule, three or four individuals are met with. 

 At other times, especially in weakly birds, there 

 are dozens, and these fill up the lumen of the 

 intestine to such an extent that it is difficult 

 to see how food can pass along it. 



D. urogalli, like most cestodes, produces a 

 very great number of eggs at any one time. 

 It may be, at a rough estimate, at least 100,000 ; 

 but this figure is no measure of the reproduc- 

 tivity of the cestode, because as fast as new 

 segments break off at one end, new ones are 

 formed just behind the head, and the animal 

 goes on producing new segments very much in 

 the same way as a recurring decimal reproduces 

 cyphers. Hence the eggs of this cestode must 

 be scattered in countless millions all over the 

 grouse moors. They are probably eaten by some 

 insect or land mollusc, and in the body of these 

 invertebrates, change into the " cysticercus " or 

 larval stage. 



The popular notion that grouse do not eat 

 animal food is entirely wrong. For the first 

 three weeks of the bird's life the greater part 

 of its diet consists of insects or arachnids, and 

 from the crop of the first grouse I ever dissected 



