MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



119 



Immediately after molting one can see the fluids of the body under the neck; the head is 

 cherry-red, while the suranal plate, anal and other abdominal, and also the thoracic legs are pale 

 carneous. . 



Stdf/e TL — Length at first, 20 mm., becoming the next day 23-2.5 mm. Body as before, but 

 the stripes are blackish red, there being no other change of importance. The suranal plate is a 

 little larger than before. 



Last starjr. — Length, 40 mm. Head large, black, as wide as the body. Prothoracic shield 

 dark reddish black.. 



The stripes are of the same relative width as in Stage III, but have lost their red coh>r, and 

 are brown-black, while the yellow of the body has a greenish tinge. There is no red at all on the 

 prothoracic segment or on tlie legs or on any part of the body. The suranal plate is large and 

 black, the black median dorsal line wider on the segment in 

 front. The hairs are now whitish and thicker than in theprevious 

 stages. 



1 notice that the hairs on the thoracic segments have at 

 times an individual motion, and are jerked one way and another, 

 as also the warts wliich give rise to them. 



When irritated it discharges a drop of green fluid, its partly 

 digested food. 



One x>upated September 20, and another a little later. 



Fupa. — Body long, but not very thick. Head projecting 

 in front, with three ridges, one median. Cremaster with four 

 long equal acute spines, the i)oints long and tapering, almost 

 setiferous; surface rugose. A lateral small, stout spine on each 

 side of the base. The vestiges of the $ sexual opening broad, 

 ■with a round tubercle on each side. Surface of the body 

 corrugated with confluent i)nnctures on head and thorax; abdo- 

 men coarsely punctured. Length, 22 mm. 



Food plants. — Sumac (Rhus (ilahra and R. typhina) (Miss 

 Morton, Mr. ])yar. Dr. C. V. Riley). 



Habits. — Larva' occurring in July and September; motbsin 

 June, July, and September (Riley). 



Geo(iraphicaJ distribution. — Chicago, 111. (Westcott); Colo 

 rado Springs, Colo., June 2."), at light (Gillette); West Farms, 

 N. Y. (Angus); Newburg, N. Y. (Miss Morton); New Jersey and 



Pennsylvania (Palm); Chicago, 111. (Bolter); Manhattan, Kans. (Popenoe); Colorado (Edwards 

 Coll. Amer. Mus. Nat. Hist., N. Y.); Illinois (Strecker); Mr. Dyar has received this species from 

 Miles City, central Montana; Missouri, District of Columbia, Kansas, Virginia, and New York 

 (U. S. Nat. Mus.); New York, Pennsylvania, Wisconsin, Jlissouri, Carbondale, 111. (French). 



Fig. 61.— Puii.1 of Dataiut pcrspicita. 



Datana robusta Strecker. 



(PI. II, fig. 16, <?; 17,9.) 



Iialana robusta .Streck., I.,ep. iml. and Esot.,p. 131, 1872. 

 Smith, List Lep. Bor. Aiiier., p. 30, 1891. 

 Kirby, .S.vii. Cut. Lep. Het., i. p. 613, 1892. 



Neum. anil Dyar, Tran.s. Amer. Ent. Soc, xxi, p. 199, 1894: Jourii. X. Y. Eut. Soc, ii, p. 116, 

 1891. 



Moth. — Closely allied to J>. pt-rspicua and marked in exactly the same way. The outer margin 

 of primaries seems less distinctly scalloped. Thoracic patch ocher-yellow, shading into tawny 

 posteriorly exactly as in D. perspicua, or entirely ocher-yellow, with only a few tawny scales 

 defining its posterior border. In this latter case it is paler than the thorax. Thorax and primaries 

 clay color (R., V, 8, a little paler), heavily dusted with hazel scales (R., IV, 12), these predominating 

 in the space between first and fifth lines below the median vein, all throughout giving a dark 

 cast to the wing; lines, spots, and fringe, as in J), perspicna, or rather fainter. Rarely, only the 

 outer Hues are discernible. Median venules marked with brown rather more heavily than in D. 



