264 



THE AMERICAN 



weather is hot, they get iu the shade ; and then 

 they never have any web or particnlar place they 

 return to, or show any tiuiformitj^ in the size of 

 the bunches. But they only manage in this way 

 while the leaves last. As soon as one tree is strip- 

 ped they go to another, and when one orchard is 

 used up leave for another. They are great trav- 

 elers ; on a smooth track, like a liard road or a 

 fence cap-board, they get along quite fast. They 

 do not try to keep together, but each one goes 

 on his own hook. There is very little said about 

 the Tent-caterpillar of the Forest traveling in 

 this wa)^ 



Then our larvaj appear decidedly to prefer the 

 leaves of the Apple-tree, and only feed on the 

 leaves of other trees when the former arc not to 

 be had. Though I am not prepared to say that 

 they will not feed on Oak, Walnut or Hickory 

 trees, under any circumstances, I have repeatedly 

 found these trees in full leaf when not only Apple 

 trees, but Ash and Basswood trees near by, 

 were entirely stripped. The eggs are sometimes 

 laid on Hard Maple sliade trees, but the cater- 

 pillars leave these trees as soon as they get much 

 size, evidently in search of food more suitable to 

 their taste. This may be the case iu regard to 

 Oak and Walnut trees. 



They also select different places for their co- 

 coons. Dr. Fitch says the Tent-caterpillar of 

 the Forest selects a sheltered spot for its cocoon, 

 such as the corner or angle formed by the meet- 

 ing of two or three sides. In this the cocoon is 

 susx^endcd. Our larva selects one or more leaves 

 on any tree that is convenient. The edges of 

 the leaves are drawn together, forming a shelter 

 in which thci'e is generally one cocoon ; tlaough 

 when the space is large, and they are very 

 ]iumerous, there are often two or three cocoons 

 together. The cocoon is not suspended, but 

 fastened to the leaf. They spin their cocoons in 

 the forepart of July, and the moths appear in 

 the latter part of the month. The Tent-cater- 

 pillar of the Forest, spijis its cocoon about tlic 

 L'Oth of June, and the moth appears in the fore- 

 part of July. 



Now I (hink enough has lieeu given to show 

 that two distinct insects are under consideration, 

 but, being only a farmer, I may be mistaken. I 

 would like to see Dr. Fitch"s views on this ques- 

 tion. Undoubtedly he has read Dr. Walsh's ar- 

 ticle on " Tlie Thr(3e so-called Army-worms," in 

 the Practical Entomologist, and can tell whether 

 our caterpillar is a distinct insect, or only shows 

 the variations that may be expected in the Tent- 

 caterpillar of the Forest. 



Now since Dr. Fitch Jias not, to our knowl- 

 edge, complied with Mr. Ferris's courteous wish, 

 we shall have to do so ourselves. We have taken 

 upwards of 200 specimens from the same batch 

 of Oak-feeding worms, and upon critically ex- 

 amining them, find that Dr. Fitch's desci-iption 

 is accurate, and that the differences or variations 

 mentioned by Mr. Ferris arise in every case, 

 either from a misapprehension of Dr. Fitch's 

 meaning, or from variations which may be found 

 in the same brood. Tlie only real difference 

 between the two writers lies in the statement of 

 Dr. Fitch that the worms live under a large cob- 



web-like nest, and that of Mr. Ferris that they 

 do no such thing. Both statements should have 

 been qualified, and were made without sufficient 

 observation ; for though the normal liabit of the 

 worms is to collect outside of their nests, we 

 have seen exceptional instances of their collect- 

 ing within or underneath it, especially when 

 young. 



Now it is just barely possible that, in Western 

 New York there may be a race of these worms 

 that has taken to feeding on Apple and has lost 

 all ap]3ctite or become incapacitated for feeding 

 on forest trees ; in other words, that there is a 

 phytophagic variety, or a phytophagic species in 

 process of formation. We could mention several 

 similar occurrences among insects,* and to those 

 who believe iu the immutability of species these 

 occurrences are incomprehensible enough ; but 

 to those who accept the more modern Darwinian 

 views, and believe that species are slowly being 

 formed to-day, just as they have been for long 

 ages and ages iu the past, they are most signifi- 

 cant, and exactly what we should expect. But 

 that such a race has yet been formed is rendered 

 highly improbable from the following facts : 1st. 

 It is spoken of both by Dr. Fitch and Dr. Harris 

 as occurring on Oak, and by the latter as also 

 occurring on Walnut, Apple and Cherry in the 

 New England States. George E. Brackett, of 

 Belfast, Me.,t in referring to its ravages in the 

 orchard, states that it also ravaged the forests in 

 the summer of 18(57, eating the leaves of most 

 kinds of deciduous trees, though Poplar and Ash 

 seemed to be their favorites. 2nd. We have, in 

 this section, successfully transferred them from 

 Oak to Apple, and from Apple to Oak, and now 

 liave a suite of moths bred from larvie which 

 were fed half the time on the one and half the 

 time on the other. Given an equal quantity of 

 Oak, Apple, Plum, Peach, Cherry, Walnut, Hick- 

 ory, Rose, they have invariably seemed to prefer 

 and thrive best on the Apple. 



IS IT KVER VERY DESTRUCTIVE? 



This questicni is raised by Dr. Fitch, who, on 

 insufficient grounds, discredited the previous 

 assertion of Abbot, that it " is sometimes so 



» For an account of such insects as are known to have phy- 

 tophagic varieties or phytophagic species we must refer the 

 reader to Mr. Walsh's papers on tlie subject in the I'roceed- 

 injrs of the Entomological Society of Philadelphia lor ISiit 

 .lud 18(15 But, as the most familiar and striking examples 

 we will mention, lirst— the polyphagous bhick-iieiieilled larva 

 of Halesidola tassdiata, Sm and Abb,, lound Keding on 

 Oak, lliekorv. Elm, Plum and other trves, and Uie niono- 

 ]ilKigous orangf-pcncilled larva of H. Hdnisii, ^Vul,sll, found 

 exclusively on fSycamore; the moths from the two beiuK 

 absolutely" niidi.sringuishable. Second — the yellow-neckeu 

 ]:ivv:i lA' Dnliiiin iiiinistra, Drury, found on Apple and other 

 trees, and tlie black-necked larva of the same nuith found 

 on lilack Walnut ami Hickory. Third— the large JSiitternut 

 and Walnut-feeding form of the common I'liim Ciirculio 

 (Conotrachelus nenuphar^ Herbst.) 



tAmer. Jour. ofHort., Sept., 18G7. 



