1448 THK BUTTERFLIES OF NEW ENGLAND. 



broad field, tlie inferior arinatiire, well provided witli spines or Ijristles. Besides the 

 asymmetry of the dorsal crest referred to, the lateral arms, the terminal hooks and 

 the inferior armature, frequently partake of the same peculiarity; indeed, this ele- 

 ment seems to pervade every part of the remarkable genital armature in this genus. 

 With some minor exceptions, the left clasp is always more highly developed than the 

 right, both in the configuration of the whole, aud in the sculpture and armature of 

 the details ; each clasp may be divided, for convenience of description, into two parts 

 — an upper and a lower; the upper portion is ordinarily developed as a broad lobe, 

 armed on its upper edge with a row of very long, stifl' bristles, pointing backward, 

 not exhibited on the plate; it has a tendency to expand in two directions, form- 

 ing what are called the ui)per and hind processes, according to their position; the lobe 

 is generally smaller in the left clasp than in the right; and the hind process either 

 wanting or minute in the left. The lower part of the clasp is a very long, slender, 

 usually compressed, often twisted and invariably curving blade, frequently spined or 

 pointed at tip, its origin marked below by a denticle; it bears, at the base of the 

 upper edge, a short, frequently bent or curving process, ordinarily somewhat trian- 

 gular in shape, and very often armed with spinules ; sometimes this process is wanting 

 on the right clasp, and it is usually more slender and frequently longer on the left 

 than on the opposite side; at their base the clasps form a large, broad, compressed, 

 somewhat gibbous plate of variable form. 



The movement of the clasps is of course lateral, and that of the upper organ ver- 

 tical ; but some of the constituent parts of the latter have an independent motion, 

 the whole central apparatus, including the hooks, having a common vertical movement 

 upon the centrum and the central tooth a forward aud backward swing upon the apical 

 portion. 



Egg. Very short, sugar-loaf shaped, the sides narrowing upwards but rounding 

 very little, excepting above, scarcely broader than high, broadest in middle of lower 

 half, the base squarely docked, its rim rounded, the summit broadly rounded, depressed 

 somewhat in the middle; furnished with a moderate number of straight, not very 

 prominent, vertical ribs, extending from the base to the micropyle, the surface 

 between them depressed in regular curves ; traversed also by numerous, delicate, trans- 

 verse, raised lines. Micropyle rosette a little depressed, consisting of a few rather 

 large, roundish oval or kite-shaped plates surrounding a central minute circle and 

 bounded by a number of oval, angular cells, the outermost larger than the others. 



Caterpillar at birth. Head orl)icular, minutely granulated, scarcely broader than 

 the thoracic, scarcely smaller than the middle of the abdominal, part of the body, fur- 

 nished with scattered, simple, tapering, but aplcally expanding hairs. Body slender, 

 equal, the first thoracic segment with a very obscure dorsal shield, furnished with a 

 double transverse row of four equidistant bristles, besides a pair of long, forward 

 curving, infrastigraatal bristles (86 : 48-51). The abdominal segments supplied with 

 the following series of aplcally expanding bristles : a laterodorsal series, anteriorly 

 placed (supralateral in some species) , becoming subdorsal and posteriorly placed on the 

 thoracic segments; a lateral series posteriorly placed on all the segments, and in each of 

 these two rows one bristle to a segment in each row : a suprastigraatal series dii-ectly 

 above the stigmata, oue to a segment on the abdominal and two to a segment on the 

 thoracic segments; and an infrastigmatal series, either one to a segment placed in the 

 middle of the thoracic segments, or two to a segment one before and one behind the 

 middle on the abdominal segments. The bristles of the upper rows are much more 

 expanded aplcally than are the others, and the long, infrastigmatal bristles of the first 

 thoracic segment, like those of the head, are but slightly expanded. 



Mature caterpillar. Head rounded, subquadrate, with full rounded sides, the 

 summit laterally augulated, and forming by the slight median excision of the centre 

 a slightly elevated, lateral, submammilate prominence, made more conspicuous by the 

 greater elevation of the minute tubercles which in some species stud the whole surface of 

 the head, and in all are distinct at this point ; head produced slightly below the middle, 

 the lower part very full, much deeper below than aljove, the front well rounded on a 



