656 PROCEEDINGS OP THE AMERICAN ACADEMY. 



the cervical plate is a slight vestige of a tubercle in front of but a little 

 below the spiracle ; farther down, near the base of the leg, is a decided 

 but small low tubercle bearing three setiferous spiuules ; those in the 

 same relative positiou on the 2d and 3d thoracic segments are of the 

 same size and shape. 



On each of the two hinder thoracic segments there are four small dorsal 

 tubercles in a transverse row. Each tubercle is crowned by a ring of 

 5-6 spines, with one in the centre. These and the dorsal ones on ab- 

 dominal segments 1-7 are so closely alike in size and armature that it is 

 difficult to see any difference in size between the thoracic and abdominal 

 dorsal ones. The four dorsal ones on each of the two last thoracic 

 and the first seven abdominal segments are alike in size, number, and 

 arrangement of the spinules ; there not being the usual distinction 

 which obtains in the Attacinae (Samia, Callosamia, Telea, etc.) between 

 the submedian (dorsal) and supraspiracular series. Those of the 7th 

 abdominal segment are, as far as I can see, just like those on the 2d and 

 3d thoracic and 1st abdominal segments. 



The median spine on the 8th abdominal segment is scarcely higher 

 (longer), but is about one-quarter thicker than the one on each side ; it 

 is slightly broader than long (seen in section from above) and bears five 

 spinules on each side of the median line. There is no infraspiracular 

 row of tubercles (such as are present in the Citheroniinae and Attacinae). 

 There also seems to be no difference in color between any of the 

 tubercles. 



The suranal plate is green, a little rough on the surface, and there, 

 are traces along the hinder edge of piliferous spines ; the plate is edged 

 with black. The anal legs are large, green, the triangular area edged 

 with black, and on the edge are scattered small black piliferous warts. 

 The thoracic legs are pea-green ; the abdominal legs green, with irregu- 

 lar rows of black warts bearing white hairs above the plantae, which 

 are, with the hooks, black. Along the side of the body extends a broad 

 lateral yellow infi'aspiracular line, from which and below which arise 

 long fine white hairs. The spiracles are sienna brown-yellow. The 

 body is covered witli fine \yhite short clavate hairs. Length 80 mm. 



An inflated example from Mexico in the U. S. National Museum, 

 collection of Dr. H. G. Dyar ; two inflated examples, in bad condition, 

 :^om Tacubaya, Mexico (Barrett). 



In the species of this genus the degree of specialization of the tuber- 

 cles in the larva is very slight, as they show a tendency to reduction 

 and atrophy, which reaches its greatest perfection in R. betis, in which 



