THE AMERICAN ENTOMOLOGIST. 



39 



TENT-CATERPILLARS AND FALL WEB-WORMS. 



The following appears in the Western Biiral 

 of August 2G, 1869, from the pen of a corres- 

 pondent: 



The Tent Caterpillar has taken possession of 

 many line young trees, and spread his web from 

 " pole to pole," for many are stripped of foliage 

 and resemble bare poles. 



The true Tent Caterpillar, or as it is often 

 briefly called, "The Caterpillar,"' hatches out in 

 the spring almost before the leaves of our apple 

 trees put forth. Early iu June they spin up, 

 and the moths, which are of a reddish brown 

 color, make their appearance early in July, 

 shortly after which they deposit their eggs in 

 the well-known rings on the twigs, of which 

 we gave a drawing (Fig. 145 c) on page 208 of 

 our first volume. The Fall Web Worm, on the 

 contrary, does not hatch out till August, and 

 although it makes a very similar web-like nest 

 to tliat constructed by the preceding species, it 

 is yet a much smaller insect and somewhat dif- 

 ferently colored. Towards the end of the sum- 

 mer this worm spins up like the true Tent Cat- 

 erpillar; but instead of the Moth bursting forth 

 from the cocoon the same season, it does not 

 make its appearance till the middle of the fol- 

 lowing season. Moreover this moth, instead 

 ot being reddish brown, is of a pure milk- 

 white color, and it does not lay its eggs in a 

 ring upon the twigs, but deposits them in an 

 irregular mass upon a loaf. Thus it will be 

 seen that one insect hybcrnates in the egg state, 

 the other in the puiJi state: one larva appears 

 iu May, the other in August; one moth is 

 brown, the other is white; and one lays its eggs 

 ou the twigs, because if it laid them on a leaf 

 they would fall off the tree and be lost iu the 

 winter, whereas the other species lays its eggs 

 on a leaf, because it is instinctively aware that 

 those eggs will hatcli out long before the leaf 

 falls to the ground. 



No two insects are more frequently con- 

 founded than the true Tent Caterpillar (C/isio- 

 cam2m americana, Harris), and the Fall Web 

 Worm {Hyphantria textor, Harris) ; so that the 

 correspondent of the Western Bural will find 

 plenty of company in the mistake that he has 

 made, in speaking of Tent Caterpillars in Au- 

 gust. Both species are very general feeders, 

 the nests of the Teat Cate.'-pillar being found on 

 the Wild Black Clierry, the Apple, the Crab, 

 the Choke Cherry, the cultivated Cherry, the 

 Plum both wild and tame, the Thorn, and the 

 Shad bush, but scarcely ever on the Pear or on 

 the Peach ; while those of the Fall Web Worm 

 occur in the greatest abundance ou Hickories, 



especially the Pignut Hickory, and also ou Wild 

 Black Cherry, Apple, Crab, Ash, Elm, Willow, 

 Oak, Birch, and Sycamore or Buttonwood. 



EXPERIMENTS WITH THE JAPANESE SILK-WOKM. 



{Aniherca Yama-mai.) 



In the year 1868 I made some experiments in 

 rearing the Ailanthus Silk-worm {Samia Cyn- 

 thia), 9.n account of which appeared in the Ainer- 

 ican N'aturalist, iu the August number of that 

 year. I was of opinion then, and am now, that 

 Cynthia is the moth best adapted to our north- 

 ern climate as a silk-producer. My reasons 

 need not be repeated here, but I may say that, 

 since writing the article above adverted to, I 

 have received from Dr. Wallace, of England, a 

 specimen of sewing silk made from the cocoon 

 of the Cynthia, and its appearance and quality 

 have strengthened ray previous favorable 

 opinion. 



By way, however, of ascertaining the species 

 of silk-worm moth most suitable to the climate 

 of North America, I obtained from Dr. Wal- 

 lace a iramber of the eggs of the Japanese silk- 

 vvrorm known as Yama-mai, which is said to 

 produce a most beautiful silk, of a greenish 

 color, and the cocoons of which are as easily 

 reeled as are those of the ordinary silk-worm 

 {Bombyx mori) . These eggs were sold to per- 



I sons residing iu widely distant localities, while 



' I reserved a considerable number for my own 

 use. 



I propose in this paper to give the readers of 

 the EsTOMOLOGiST not only au account of my 

 own experiments with this insect, but also a 

 synopsis of the results of the experiments of my 

 correspondents, so far as I have been able to 

 ascertain them. 



The whole of the eggs I received from Eng- 

 land arrived in New York iu the nionlhs of 

 March and April. lam inclined tolhiuk lliatthis 

 is a bad time to receive them here, and that in 

 future it will be better to receive them in the 

 fall, so that they may be forwarded to their res- 

 pective destinations before the severe cold sets 

 in, thus enabling parlies living in widely dis- 

 tant latitudes to keep their eggs at a tempera- 

 ture which, without injuring the egg, will re- 



I tard the hatching till such time as vegetation 

 iu their respective localities shall be so far ad- 



! vauced as to afford the caterpillars a good sup- 

 ply of food. If the eggs be kept in England till 

 early spring, it is clear that they will be some- 

 what developed by the warmth of the climate, 



