MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 207 



a shiny brown, with two points at the tail and one blunter one at the head. There are also slight 

 elevations on the under part of the abdomen where the prolegs of the caterpilhir were. 



"The mimicry of the larva when on the blackberry, eitlier stem or leaf, is perfect, and the 

 imitative resemblance of the moth, when at rest, to the bark of a tree is still more striking. The 

 moth always rests head downward with tlie legs all drawn together and its wings folded round 

 the body, which is stretclied out at an angle of about 4.5 degrees, the dull gray coloring of the 

 wings with the lichen-green and tlesh color giving the whole such a perfect appearance to a piece 

 of rough bark that the deception is perfect. 



"Some of the larva; are, however, infested with Tachinids and witli Opliion purgatoi- Say." 

 (liiley's uni)ublished notes.) 



Fooil phdits. — Apple, plum, thorn (Cratwrjus), ehn, and probably poplar (Packard), BetuJa alba 

 (Mrs. Dimmock); hazel {Conjhis americana), FniiiK.s virginiana (Lintner); Frinos rerticiUatus 

 (Abbot); hicust, cherry, dogwood, alder, ilex, oalv (lieutenmiiller). 



Gcofjrajjiiical dLsfribiitidii. — Common throughout th(^ Appalachian and Austroriparian sub- 

 j)roviiices. Its western limits not yet defined, though it inhabits Napa County, Cal., according 

 to Edwards. 



Canada (Saunders); Orono, Me. (Mrs. Fernald); Ijrunswick, Me. (Packard); Franconia, N. H. 

 (Mrs. Sh)SSon, and a fresh one was captured by her in the Summit House, on Mount Washington, 

 New Hamjjshire, at the end of July); Boston, Mass. (Harris, Shurtleft, Sanborn); Rliode Island 

 (Clark); New York (Grote, Lintner, Dyar); Plattsburg, N. Y'. (Hudson); Eacine, Wis. (Emma 

 Payne) ; ^Manhattan, Ivans. (Popeiioe) ; Amherst, Mass. (ilrs. Fernald) ; Georgia (Abbot and Smith) ; 

 Napa County, Cal. (H. Edwards); Canada, Kittei-y, Me.; New Hampshire, New Y'ork, Ohio, 

 Wisconsin (French). 



Summari/ of the sicpn in the asminipihin of the (jeneric or aduptire, i, e., protective characters of three 

 species of Schizura (»S'. ipomea', hptinoides,and unicornis). 



The sunergeneric features of the partly elevated, uplifted anal legs and a difference in the 

 size of the tubercles appear at tin; time of liatcliiiig. 



1. Tlie head becomes marked much as in the adult in the second stage. 



2. The tubercles begin to be differentiated in the second stage, when the prothoracie tubercles 

 are much smaller than in the first. 



3. The tubercles of the first abdominal segment, originally separate, become united at the 

 base in the third, and foi'n a single liigh-forked tubercle in the fourth stage. 



4. The glandular hairs differ geiierically in the second stage from those in the first. The 

 flattened glandular hairs appear in the second and disappear in the fourth stage. 



.5. The V-shaped dorsal mark on the sixth and seventh abdominal segments appears at the 

 end of the third stage, and is dne to the coalescence of three separate, whitish yellow si)ots. 



(j. The pea-green color of the meso- and metathoracic segments appears at the end of the 

 third stage. 



It thus appears that the mimetic colorational features, being those which especially enable the 

 larva to escape observation, appear shortly before the creature is half grown, then changes 

 occurring at the end of the third stage, while the movable terrifying tubercle of the first 

 abdominal segment becomes developed at the same time. 



When feeding oil the edge of a leaf, the Schizune exactly imitate a portion of the fresh, green, 

 serrated edge of a leaf, including a sere-brown withered spot, the angular, serrate outline of the 

 back corresjionding to the serrate outline of the edge of the leaf. And as the leaves only become 

 spotted with sere-brown markings by the end of summer, so the single-brooded caterpillars do not, 

 in the Northern States, develop so as to exhibit their jn-otective coloration until late in the 

 summer, i. e., by the middle and last of August. 



A feature of some significance is the large size of the prothoracie tubercles in the larva of the 

 first stage of (S*. ipomea% which in successive stages becomes reduced to a size no greater than 

 those of the other thoracic seffmeuts. 



