NYMPIIALIXAE : THE GENUS BRENTHIS. 581 



Mojirly at right angles to the tubercles or slightly raised above it. Tliey are arranged 

 as follows : on the abdomen, a laterodorsal scries on all the segments, placed a little 

 in advance of the middle, that on the first segment being nearly subdorsal ; a supra- 

 stigmatal on all the segments placed anteriorly, excepting on the last segment where 

 it is posterior; and an infrastigmatal series on all the segments but the last, also 

 placed anteriorly; on the thoracic segments a laterodorsal series placed in the mid- 

 dle of the segments, that of the first segment being to a greater or less extent longer 

 than any of the other spines and sometimes produced at maturity to a very long, 

 rteshy, equal, tentacular, heavy thread, covered with frequent, short, spinous needles; 

 and on the second and third segments a stigmatal row placed on the anterior 

 extremity. Body covered also irregularly with numerous, very short, needle like hairs, 

 arising from very minute warts. Spiracles small, oval, half as long again as broad. 

 Legs rather small, appressed, tapering, modei'ately slender, the claws compressed, 

 slender, small, curving somewhat, strongly heeled at the base ; prolegs short, moder- 

 ately stout, tapering a little, the booklets twenty-five to thirty in number, slender and 

 not very strongly curved, arranged in a double row and separated by a space equal to 

 two or three times the diameter of one of them. 



Chrysalis. VicAved from above, the prothorax, head and ocellar prominences are 

 i'(|ual in width; the latter project conically a little at the outer corners, separated very 

 l)roadly by the front of the head, which is squarely truncate or else very broadly con- 

 cave ; viewed laterally they are also a little prominent, especially at the lower corners ; 

 they are connected by an obscure ridge along the lower front of the head and their 

 extreme base is tumid below, laterally and above; excepting for the tumidity of the 

 lower surface, the angle formed by the front and summit of the head is about 70°. 

 Body a little constricted between the prothorax and mesothorax ; mesothorax pretty 

 strongly arched longitudinally, the anterior portion of the posterior half elevated 

 to a pretty high, longitudinal, median ridge, its anterior slope shorter than the 

 posterior when the curve of the segment is left out of account, transversely rounded 

 at summit, the sides sloping at an angle of about 50°, continued anteriorly as a dull 

 equal median ridge to the end of the segment ; front of the body from the base of 

 the palpi to near the tip of the wings a very little concave ; basal wing tubercle rather 

 prominent, conical, curved slightly forward, with a slight ridge down its inferior pos- 

 terior surface ; supernumerary tubercle very close to the basal one, separated from it 

 by a rather deep rounded angulation, the tubercle a compressed longitudinal ridge, 

 well rounded longitudinally, its anterior shorter than its posterior curve. Wings a 

 little protuberant at tip but with no tubercle; a laterodorsal series of stout, blunt, con- 

 ical tubercles on the middle of the thoracic and first to seventh abdominal segments, 

 largest and quite large on the third abdominal segment, those in front of nearly equal 

 size, excepting that on the mesothorax, which is small, those of the fourth abdominal 

 segment smallest, very small ; beyond increasing in size regularly, but all broader 

 and lower in proportion than the others, at least on the basal portion; the most 

 elevated portion of the tubercles placed toward their anterior edge, at least in 

 advance of the fourth abdominal segment. A pair of very small, rounded, suprastig- 

 matal warts a little in advance of the middle of the second to seventh abdominal 

 segments. Preanal button bounded laterally by moderately broad, low, equal, scarcely 

 curving Avails, each terminating anteriorly in a blunt, slightly appressed, nearly 

 recumbent tubercle; cremaster viewed from above very short, tapering, as long as 

 its narrowest breadth, scarcely hollowed; on a side view, expanding rapidly, espec- 

 ially beneath, as long as its greatest breadth, the area for anal booklets subtriangular, 

 longer longitudinally than broad, its base anterior. Body covered very sparsely 

 with exceedingly delicate, short hairs, invisible to the unassisted eye. Hooklets short, 

 slender, compressed, the stem straight, the crook considerably enlarged, bent roundly 

 at right angles, the pointed apex very short. 



Distribution. This group is even richer in species than Ai-gynnis, and 

 has a wider geographical extension, embracing not only the north temper- 



