294 PROCEEDINGS OF THE ACADEMY OF [1884. 



of the dread lest the children should imbibe one with their 

 frequent nips of the water, so I sat down, one warm afternoon, to 

 watch the pail, to try to learn how the snakes came. In about 

 ten minutes I saw a particular!}' plethoric cricket mount upon 

 the edge of the pail, and, after some uneasy movements, bring 

 the tip of the abdomen just beneath the water, and, with a few 

 violent throes, expel a black mass, which fell slowly through the 

 water, and before it reached the bottom resolved itself into one 

 of the worms. The cricket seemed exhausted by the horrid 

 birth, and did not find strength to draw itself up on the edge of 

 the pail for about eight minutes, and when it finally did so, it 

 tumbled to the floor and crawled off in a very rheumatic manner. 

 After this discovery, we used to amuse leisure hours by watching 

 like operations until fi'ost killed the crickets. I sometimes would 

 crush large crickets, generallj" with the result that a tightl}'- 

 coiled snake would be thrust out of a rupture just above the tip 

 of the abdomen ; but, whether the snake was not sufficiently 

 developed, or because of its needing water rather than air to 

 vitalize it, none of the snakes so produced showed any signs of 

 life." 



The water snake alluded to is, of course, a species of our 

 common Gordins, the same probably as that described, a number 

 of years ago, by our distinguished President, Prof. Jos. Leidy. 

 The fact that this animal is parasitic within the grasshopper, the 

 speaker had himself observed ; it has been said also to be para- 

 sitic within spiders, and doubtless has for its host many of the 

 orthopterous genera. The point of greatest interest in the letter. 

 Dr. McCook thought, is the fact that the crickets had evidently 

 learned that the parasite infesting them required the water in 

 order to make its egress, and had deliberately sought the suitable 

 place and assumed the proper position (by inserting the abdomen 

 beneath the surface of the water), necessary to insure that egress. 

 It is a curious physiological question : how did the cricket obtain 

 this knowledge? And, the knowledge having been obtained, the 

 cricket's subsequent behavior presents an interesting fact in the 

 study of insect intelligence. 



A New Parasitic Insect upon Spider Eggs. — Dr. McCooK 

 further stated that he had received, through Mr. F. M. Webster 

 (October, 1884), from Oxford, Indiana, a parasitised spider 

 cocoon (evidentl}^ of some saltigrade species), apparentl}' that of 

 Alius audax. The cocoon contained within the outer flossy case 

 about eighty cells and a number of mature black hymenopterous 

 insects, about one-eighth of an inch long. The cells were ovoid, 

 gray, blackish at the closed end, probably from excretions of the 

 enclosed larvae. One end was cut open, showing where the insect 

 had escaped. With the exception of a few hard, dried, yellowish 

 brown examples, all the eggs of the spider had disappeared. 

 The specimens were sent to Mr. L. 0. Howard, of the Bureau of 



