MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 205 



.unicornis. This appears to be a climatic variety, following the same law of climatic variation as 

 we have already referred to. 



Egg, "Greenish to veHowisli gray in color; transverse diameter, S mm.; hemispherical, not 



flattened; surface under liigli power, with elevated ridges forming facets. A slight iireguhir 

 Toughening occurs about the niicropylar region." ("Deposited in captivity in Feb." Eiley .AIS.) 



Larva.— The first stage of (S*. unicornis differs but slightly from that of aS'. ipomea'. Lengtli, 

 2 mm. The head and body are of the same proportions, the prothoracic tubercles of nearly the 

 same size, but those on the back of the nieso- and metathoracic segments are larger than in <S'. 

 vnicornis. The tubercles on the abdominal segments are of nearly the same proportions, but 

 slightly larger. 



The first, third, and eighth abdominal segments are bright red in unicornis as in ipomeK, and 

 the colors and markings iu general scarcely different from those of ipomem. The anal legs are the 

 same in size and position in the two species, but the tubercles are on tlie whole larger in ipomew. 



The hairs are clavate in unicornis and of the same proportionate length as in ipomea-. 



It thus appears that no genuine specific differences exist between the freshly hatched larviB 

 of S. ipomea- and unicornis iind most probably Icptinoiiles, though the caterpillars are so different 

 when fully fed. On the other hand, though we do not know the earliest stages of the other species 

 of Schizura, yet from our knowledge of those of Dasylophia anguina there seems little doubt that 

 the generic characters are ([uite clearly indicated iii the first stage; that is, it will always be easy 

 to separate Schizura larva' just after hatching from those of any other genus of Notodontians, 

 while if specimens of S. ipomea and unicornis of the first stage were mixed together it would be 

 almost impossible to safely separate them according to the species, the incipient specific characters 

 actually existing being too slight and indecisive. 



Length, 20 mm. Body much compressed; head not so wide as the body, compressed, flattened 

 in front, elevated toward the vertex, cleft, ending in two rounded conical tubercles, pale rustred, 

 densely marbled with a fine net-work of darker lines. Body pale rust-red, with a pale pea-green 

 patch on the side of the second and third thoracic segments, not reacliing to the anterior spiracle. 

 First abdominal segment with a large high acute conical tubercle, bearing at tip two very 

 slender, spreading, brown cylindrical tubercles. On fifth a slight hump, bearing two small 

 warts; eighth segment bearing a ratlier large dorsal hump, supporting two dark warts; in front is 

 a broken V-shaped silver mark, the apex directed forward. Anal legs brown, held out, with end 

 of body, horizontally. Three lateral obscure, oblique lines connecting with a dark, pbscure, lateral 

 straight line placed some distance above the spiracles. Feet all rust-reddish, thoracic feet paler. 



Length, 2.") mm. Has a shorter smaller dorsal retractile tubercle than iu .S'. ipomea: Thoracic 

 segments pea-green; the dorsal V-shaped mark on the seventh segment is iiroloiiged to the front 

 edge of the sixth segment, this part really forming a separate narrow V, in front of the apex, of 

 which on fourth and fifth segments each is a dusky brown patch, between tlie reddish brown 

 piliferous warts. 



Before the last molt the larva is the same as the mature form. Length, 13 to 18 mm. 



The dorsal hump is not so soft and retractile or sensitive as in the larva of S. leptinoides. 



"It is a very singularly shaped caterpillar. General color in sound specimens, rich reddish 

 brown, iu others grayish brown, sliaded with very minute spots of a darker color, which give it a 

 shagreened appearance. A faint line of a darker color runs along each side from the third segment. 

 It is Variegated on the back with a lighter color, somewhat in the shape of a letter W as one looks 

 from the head, and two lines forming a V mark. 



"Larvte found on the blackberry were mostly very i)ale, with the white Y mark on joints 9 

 and 10 very plain, with much glaucous color about the back, and with the other shades of purple- 

 brown, flesh-browu, olive and pale green, which are found on tlie withering blackberry bushes, 

 all present. The glaucous and brown colors are especially noticed on the canes of this plant." 

 (Eiley in Fifth Bep. V. S. Ent. Comm., p. 260.) 



Cocoon. — "Thin and ahnost transparent, resembling parchment in texture, and covered generally 

 with bits of leaves on the outside" (Harris). The larva spins a silk. cocoon with the debris on the 

 outside, judging by a specimen in the United States National Museum. 



