ORTMANN: THE CRAWFISHES OF THE STATE OF PENNSYLVANIA 495 
dentally, but must have been brought in by the crawfish. In one case (October 9, 
1905, Nine-Mile Run), I found in a side-pocket of a hole of a female C. monongalen- 
sis anumber of ripe fruits of Crategus, about a handful, which under no circum- 
stances could have fallen into the position where they were found. The hole was 
under a large Crategus bush. 
Thus it seems that any vegetable or animal matter, either fresh, or decaying, 
serves as food for crawfishes, and although some species may prefer certain classes of 
food on account of taste or necessity, they all take readily to any kind, as is seen by 
the fact that in captivity they eat everything that is offered to them without dis- 
crimination. If nothing is given, they eat one another. 
Crawfishes in turn serve as food for many animals, chiefly those which are 
aquatic. Among mammals we know that raccoons hunt for them. As has been 
mentioned above, birds eat them, and the kingfisher and other equatic birds do so 
quite regularly. The report of Audubon, (see Ortman, 1900, p. 1250), that the White 
Ibis captures the chimney-builders by throwing fragments of the chimney into the 
hole, and watching for the crawfish to come up, does not seem strange to me. At 
Ohiopyle I was told that a domesticated turkey kept upon the grounds of the hotel 
had the habit of watching the holes of C. carolinus, and that frequently he captured 
this species. I have myself seen this turkey standing motionless before a hole, but 
I did not observe the actual capture. I do not entertain the slightest doubt that 
this and other birds are able to catch crawfishes in this way, and do not think that 
it is necessary to drop dirt into the hole, since the crawfish comes up frequently on 
its own account, when it may be seized. 
Crawfishes constitute an important part of the diet of certain snakes, more par- 
ticularly of the water-snakes, Natrix sipedon and leberis. I have seen the latter dis- 
gorge C. obscwrus when captured. (See also Atkinson, Ann. Carn. Mus., I. 1901, p. 
149, 150.) On two occasions I have found garter snakes, Hutznia sirtalis, in holes of 
C. monongalensis; two specimens of this snake in one hole on October 18, 1904, 
(Fern Hollow), and one snake in a hole on October 28, 1905, (Edgewood Park). 
However, whether the snakes were after the crawfishes, or whether they simply were 
using the holes for winter quarters, remains doubtful. 
Professor H. A. Surface writes to me that Cryptobranchus allegheniensis and Nec- 
turus maculosus are among the chief enemies of the crawfishes, and, indeed, these 
two salamanders are generally found at places where crawfishes abound. (Compare 
Eydeshymer, American Naturalist, XL, 1906, p. 128.) 
They are, however, most valuable as food for the fish-fauna of our waters. As 
has been mentioned above, crawfishes are good bait for certain fishes, and it is very 
