110 THE BUTTERFLIES OF XEW ENGLAND. 



what shai-ply l)etweeii the halves of the mesoscutum at about a riuht anii^le, the suture 

 between the two fomning a pronounced sulcation, the posterior curve, formed by the 

 two together, elliptic. Metathorax separated rather prominently from the mesothorax. 

 Wings of every variety of shape found amongst butterflies. Fore wings : costal 

 uervure terminating near the middle of the costal border; subcostal nervure Avith four 

 superior and tAvo inferior simple branches, at least one of which is emitted Ijefore the 

 end of the cell, — itself terminating quite near the apex of the wing; the discoi- 

 dal cell may be either closed or partially open and is of moderate Avidth; median 

 nervure with three branches, itself not reaching the border; internal ner\ure, wlien 

 present, very short and running into the snbmedian nervure. Hind wings : costal ner- 

 vure terminating betAveen the middle and the tip of the costal border, emitting from 

 near the base an upAvard directed branch, curving iuAvard or outAvard or Y-shaped at 

 the tip; subcostal nervure Avith three branches, itself not reaching the border; the dis- 

 coidal cell either open or closed; median nervure Avitli three branches, itself not 

 reaching the border ; snbmedian nervure usually terminating at the anal angle, some- 

 times on the outer border ; internal nervure usually terminating on the inner border, 

 sometimes at the anal angle. Inner margin expanded, embracing the abdomen beneath. 

 Fore legs atrophied, especially in the male; but in both sexes, the claAvs and other 

 terminal appendages of the last tarsal joints (excepting in the Libytheinae, Avhere the 

 claAvs, etc., are present in the female tarsus) and both spines and spurs of the tibiae are 

 obsolete ; the spines and sometimes the spurs of the tarsi are also absent ; in some 

 males, the tarsi are not even divided into joints and they are ahvays unarmed. 



Last dorsal segment of the male abdomen (excepting in the Lilwtheinae) entire above, 

 the upper organ generally stout, Avith or Avithont lateral arms, and provided Avith an elon- 

 gate, tapering, pointed median hook (in Libythea acicular), or if bifurcate only mi- 

 nutely excised at tip ; clasps forming lateral, lamellate, more or less convex plates very 

 variable in shape, proportion and armature. 



Egg. Globular or dome-shaped, the surface marked either Avith polygonal cells 

 (Avhose Avails may be either slight or prominent) , or else furnished Avith a number of 

 raised longitudinal ribs, usually extending over the Avhole egg, but sometimes couflned 

 to the upper half and Avith much more delicate cross-ridges. 



Caterpillar at birth. Head generally larger, never smaller, than the thoracic seg- 

 ments and usually roughened, and ahvays Avitli a greater or smaller number of hair- 

 emitting papillae; never encroached upon by the integument of the llrst thoracic 

 segment. Body cylindrical, often tapering from in front backAvard, but rarely if ever 

 from the middle forAvard, furnished Avith longitudinally ranged cuticular appendages 

 of A'arious shapes, generally longer than the segments and often more or less clubbed, 

 sonae of the series shifted in position in passing from the thoracic to the abdominal 

 segments ; flrst thoracic segment Avith no distinct corneous dorsal shield. 



Mature caterpillar. Head free, furnished to a greater or less extent Avith hairs 

 and sometimes Avith spinous processes. Body nearly or quite cylindical, long and 

 slender, equal or tapering toAvard either or botli ends ; or, single segments may be 

 sAvollen AvhoUy or in part, and then the caterpillar becomes distinctly moniliform; 

 simply furnished Avith short hairs or bristles arising fi'om minute papillae, or else sup- 

 plied Avith unequally or regularly distri))uted spines or fleshy tubercles; spiracle of the 

 eighth abdominal segment on a line Avith the others. 



Chrysalis. Either suspended by the posterior extremity only, head dowuAvard, or, 

 in rare instances, Avith no fastenings Avhatever, transforming in an imperfect cell upon 

 or beneath the ground, Avith little or no silken lining. The chi-ysalis is comparatively 

 long and slender, enlarged in tlie middle and tapering, generally to a considerable extent, 

 at either end; head advanced in front of the prothorax ; ocellar prominences double, 

 nearly ahvays present at the side of tlic head; al)domen, Avith rare exceptions, destitute 

 of a lateral ridge; cremaster stout, protul)erant, the booklets at tip modei-ately long 

 and rather slender (in rare cases aborted), their apical portion thickened equally, or 

 sometimes compressed, bent over like a crook, the apex conical. 



