INSECTS OF THE HORSE CHESTNUT. 655 



A caterpillar examined on May 13, 1881, was 1 centimeter long, semi-transparent, 

 yellowish in color, with a yellow head, and this appearance was retained, except 

 that the caterpillar became a little darker, until it went into the pupal state, about 

 May 20. 



It was difficult to see what the caterpillars lived upon, as the fresh leaves that I 

 put with them were not attacked. I have noted this point for several years and have 

 come to the conclusion that the food of the larva is the dead dry leaf in which it is 

 rolled up. I have looked carefully on the trees and can find no eaten or nibbled leaves 

 near those containing the caterpillars, so, apparentlj', its habit is the same, in this 

 respect, both in captivity and in its native habitat. 



On June 9, fifteen days after entering the pupal state, the first moth emerged. It 

 was small, with a peculiar hopping flight, the forewing mottled black and white, 

 and the hind wing more uniform in color, dusky, and slightly spotted with black 

 near the tip. 



It appears as if the second stage in the life of this insect is that in which it most 

 frequently falls a prey to its foes. During its earliest existence it is sheltered in the 

 tunnel it has bored in the stalk, and there seems no cause but the want of room to 

 prevent its remaining there and burrowing down the whole length of the stem. 

 But these quarters soon become too small for it, it leaves the tunnel by the hole at 

 which it entered, and betakes itself to the dead and curled leaf. Here it is easily 

 found by other insects, and, from the difficulty of obtaining specimens in this stage, 

 I infer that a very large number are destroyed by their enemies. 



Specimens of the perfect insect were sent to Dr. C. V. Riley and were referred by 

 him to Prof. C. H. Fernald. Though the specimens were somewhat rubbed and the 

 peculiar markings consequently faint, both these entomologists inclined to refer them 

 to Proteoteras a'sculanum, a new genus and species described by Dr. Riley in 1881,* 

 though at first there was a suspicion that the insect was Sericoris instrittana Clem.,t 

 the larval state of which was not then fully known. Specimens, however, raised 

 during the present season from larvae obtained in Ohio \ have thrown doubt on this 

 identification, but no specimen has been obtained sufficiently perfect to decide the 

 question. Dr. Riley, however, informs me that the study of a specimen bred in 1873 

 from the blossom of the buckeye, which specimen he finds specifically identical with 

 mine, renders it certain that the insect is not Proteoteras wsculanum. 



Dr. Riley has very kindly allowed me to see his notes on and figures of P. cesculanum, 

 which show several points in which that species markedly diflers from the species 

 which I reared. These points are as follows : 



(1) The larva here described bores the leaf-stalk of the buckeye and only once have 

 I found a specimen in the terminal twig. P. cesculanum bores the terminal twig as 

 well as the leaf -stalk. 



(2) P. a'sculanum bores the terminal twigs of maple {Acer dasycarpum). I have 

 never seen a specimen of this insect here described on a maple, nor have I seen a ma- 

 ple twig or leaf showing indications of its presence. 



(3) P. cesculanum often forms a swelling or pseudogall on the stem. The species 

 here alluded to never forms a gall. 



(4) P. cesculanum lives in the gall apparently through almost its whole larval stage. 

 The insect here described, however, quits the leaf-stalk at the end of two or three 

 days and lives in a roUed-up leaf. 



(5) P. cesculanum bores the stem to a depth of from 13""™ to 50™™. The insect here 

 alluded to seldom or never exceeds 13™™ in its boring. 



* See Trans. Acad. Science St. Louis, v. 4. 



t See Proc. Amer. Assoc. Advanc. Sci., 1881. 



X It is perhaps worthy of notice that among these {&w specimens (in 1882), a 

 single Loxotcenia rosaceana Harris, made its appearance. Also that although the 

 buckeye is commonly planted at my present residence, in Perry County, Pa., yet I 

 have never seen a sign of the presence of this insect upon it. 



