174 



THE AMERICAN 



following summer. During the month of June 

 they maj' be seen in pairs about the vines, and 

 we have also frequently observed around Her- 

 mann, a very closely allied but smaller and 

 different moth (Alcoloiihus faharius, Clem.) 

 about the same season of the year. This last, 

 though so closely resembling the other, may be 

 distinguished by being scarcely more than half 

 as large; by the body lacking the anal tuft and 

 being comparatively much thicker and shorter; 

 by the hind wings being comparatively larger; 

 and by the collar being of a paler orange and 

 divided on the top by a black point. 



The American Procris, though the fact is not 

 mentioned by other authors, is subject to the 

 attack of at least one para!site, with us; for we 

 have bred from it a very peculiar little four- 

 winged black fly belonging to the great Chalcis 

 family, and which Mr. Cressou, of Philadelx^hia, 

 refers doubtingly to Perilampus i^latygaster, 

 Say. 



THE DEATH WEB OF YdUNG TUOLT. 



An Enemy to Young Trout. — The Piscicul- 

 turist, Seth Green, is known throughout the 

 land for his energy and perseverance, in inquir- 

 * ing into and ascertaining the cause of auytliing 

 that may be new in his little world of interest 

 or nature. For many years Mr. Green has been 

 at a loss to account for the enormous destruc- 

 tion of very small trout, but he lias now ascer- 

 tained the cause, and gives to the public, for the 

 public good, his discovery. He says in regard 

 to the matter : 



"There is a small worm which is the favorite 

 food of trout and many other kinds offish. This 

 worm is one of the greatest enemies which the 

 small fry have. It spins a web in the water to 

 catch young fish, just as a spider does on land 

 to catch flies. I have seen them make the web 

 and catch the fish. The web is as perfect as that 

 of the spider, and as much mechanical ingenuity 

 is displayed in its construction. It is made as 

 quickly and in the same way as a spider's, by 

 fastening the threads at diflerent points and 

 going back and forth until the web is finished. 

 The threads are not strong enough to hold the 

 young trout after the umbilical sac is absorbed, 

 but the web will stick to the fins, get around 

 the head and gills, and soon kills the fish. I 

 have often seen it on the young trout, and it has 

 been a great mystery and caused me many hours, 

 days and weeks of study to find out what was 

 wound around the head and fins of my young 

 trout and killed them. I did not find out until 

 lately while watching recently hatched white- 

 fish. These are much smaller than the trout 

 when they begin to swim, and they are caught 

 and held by the web. I found ten small white- 

 fish caught in one web in one night. This web 

 was spun in a little whitefish preserve, into 



which I had put one hundred young fish. The 

 threads spun by this worm seem to be much 

 finer than the common spider's web, and they 

 are not visible in the water until the sediment 

 collects upon them. They can then be seen very 

 plainly. These webs cannot be spun where 

 thei'e is much current, and can be easily seen in 

 still water by a close observer " 



Probably hundreds of our readers have noticed 

 this web in the water, but have never stopped 

 to inquire info the matter, or whether it was a 

 worm or a spider that inhabited the submerged 

 nest and made it. It has remained for Mr. 

 Green to solve this mystery o*^ the water. 



The above item appeared originally in Wilkes' 

 Spirit of the Times, and has been quite exten- 

 sively copied. The mystery is, however, not 

 yet solved, and we shall be glad, by the aid of 

 such of our correspondents who know anything 

 about it, to give an illustrated account of this 

 mysterious worm. We have heard from Mr. 

 Green, who promises to send us specimens. He 

 informs us that " the word web hardlj- describes 

 the threads, which are not at all symmetrical 

 like the web of a spider, but in most instances 

 an irregular mass of nearly parallel threads." 

 AVe learn from Mr. Fred. Mather, of Honeoye 

 Falls, Monroe county, N. Y., who is an exten- 

 sive trout-breeder, that he has seen a web in his 

 hatching troughs, and that it often forms on the 

 eggs strong enough to lift several in a mass; 

 but that he always supposed it to be " a vege- 

 table growth or a product of the water, like 

 Byssiis." Mr. E. Sterling, of Cleveland, Ohio, 

 has also noticed the same web, and has been at 

 a loss to account for it. 



All we can at present say is, that no ex])lau- 

 ation of the fact is yet on record, other than that 

 given by Mr. Gi'een. The worm is in all pro- 

 bability the larva of some species of Caddice-fl.y 

 (PHUYGANEiuiE), for we know of no other true 

 insects that spin a web in the water. These 

 Caddice-fly larvas are case-bearers, but it was 

 long ago ascertained by Willoughby and after- 

 wards by Pictet, that many of them reside in 

 immovable cases attached to stones, etc., and 

 that they are consequently compelled to quit 

 their cases and search for food in a naked state.* 

 This may account for the fact that these cases 

 were not observed by Mr. Green, who informs 

 us that "by taking up one of the worms on a 

 twig and letting the former drop into the water, 

 a fine thread will be found attached to the lat- 

 ter." Let us hear from our piscicultural sub- 

 scribers, and living specimens of the worm will 

 also be most thankfully received. "We always 

 take delight in solving mysteries. 



MVestwootl, Iniroduciion , II, \>. G7. 



