MEMOIKS OF THE NATIONAL ACADEMY OF SCIENCES. 207 



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

 elevations on the uuder part of the abdomen where the prolegs of the eaterpillar were. 



"The mimicry of the larva when on the blackberry, either 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. Tlie 

 motli always rests head downward with the legs all drawn together and its wings folded round 

 the body, which is stretched out at an angle of about 4.") degrees, the dull gray coloring of the 

 wings with tlie lichen-green and tiesh color giving the whole such a perfect api)earance to a jiiece 

 of rough bark that the deception is perfect. 



''Some of the larvie are, however, infested with Tachinids and witli Opiiinn pinujator Say.'' 

 (Riley's un])ul)lished notes.) 



Food plants. — Apple, plum, thoru (Cratwgus), elm, and probably poplar (Packard), Betida alhn 

 (Mrs. Dimmock); hazel (Corylus umericaHu), Frunus viryiniana (Liiitner); I'riuon verticillulus 

 (Abbot); h)cust, cherry, dogwood, alder, ilex, oak (Beutenmiiller). 



Geo(/raphical di.strihiitto)i. — Common throughout the Api)alachiau and Austroriparian sub- 

 provinces. Its western limits not yet defined, though it inhabits Napa County, Cal., according 

 to Edwards. 



Canada (Sauiulers); Oroiio, Me. (Mrs. Fernald); lUunswick, Me. (Packard); Franconia, N. IT. 

 (Mrs. Slosson, aud a fresh one was captured by her in the Summit IIou.se, on Mount Washington, 

 New IIam])shire, at the end of -Tuly); Boston, Mass. (Harris, Shurtlelf, Sanborn); Rhode Island 

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

 Payne); Manhattan, Kans. (Popenoe); Amherst, Mass. (Mrs. Fernald); Georgia (Abbot and Smith); 

 Napa Couuty, Cal. (H. Edwards); Canada, Kittery, Me.; New Hampshire, New Y'ork, Ohio, 

 Wisconsin (French). 



Sitiiniiari/ of the steps in the ass^imption of the generic or adaptive, i, e., protective characters of three 

 species of Schhura (S. ipomea; leptinoides, and unicornis). 



The supergeneric features of the partly elevated, uplifted anal legs aud a difference in the 

 size of the tubercles appear at the time of hatching. 



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



a. The tubercles begin to be diflerentiated m the second stage, when the prothoracic tubercles 

 are much smaller than in the first. 



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

 base in the third, aud form a single high-foiked tubercle iu the fourth stage. 



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

 flattened glandular hairs appear iii the second and disapjiear iu tlie fourth stage. 



."). The V-shaped dorsal mark ou the sixth and seventh abdomiual segments appears at the 

 end of the third stage, and is due to the coalescence of three separate, whitish yellow spots. 



(J. The i)ea-green color of the meso- and metathoracic segments appears at the end of the 

 third stage. 



It thus appears tliat 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. 



Wlien feeding ou the edge of a leaf, the Schizune exactly imitate a portion of the fre.sh, green, 

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

 back corresponding to the serrate outline of the edge of the leaf. Aud as the leaves only become 

 si)otted with sere-brown markings by the end of summer, so the single-broodeil caterpillars do not, 

 iu the Northern States, develop so as to exhibit their protective coloration until late in the 

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



A feature of some significauce is the large .size of the prothoracic tubercles iu 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 segments. 



