550 PROCEEDINGS OF THE AMERICAN ACADEMY. 



abdominal segments. All the tubercles are uniformly dark prussian or 

 steel blue. Suranal plate yellow, except the black subtriangular patch 

 giving rise to the tubercles. Along the side below next to the base of 

 the legs is a series of detached greenish yellow spots, the two on the 2d 

 and 3d segments centred by a steel-blue minute tubercle, this being the 

 fourth on each side. Abdominal legs dark, with a yellow spot at the 

 base on the outside. 



Stage III. Described May 2d. Length 35 mm. The larva is in this 

 stage a very different creature from what it was in the previous stages. 

 It is now gorgeously colored, and a very conspicuous caterpillar. The 

 ground color of the body is pea-green, while the large swollen base of 

 each tubercle is deep reddish orange approaching vermilion, contrasting 

 with the dark steel-blue of the spines surmounting the base. 



The head is very small, not one-half as wide as the body, and one- 

 third narrower than the 1st thoracic segment. The clypeus-posterior is 

 now pale turquoise-blue, and there is a broad red-orange stripe on each 

 side of the clypeus. 



The three black spots on each segment are still large and conspicuous, 

 while those on the hinder edge are minute. The centre of the suranal 

 plate and of the anal legs is stained deep red-orange, as also the outside 

 of the mid-abdominal legs. The thoracic legs are also painted with two 

 vermilion-red rings. 



There is the same proportion between the size of the dorsal tubercles. 



The setae are scarcely as long as the spines themselves. 



Stage IV. Length 38-40 mm. Differs but little from the previous 

 stage in armature and coloration. In this stage most of the larvae have 

 the tubercles entirely black ; in a few, however, the dorsal ones on the 

 2d and 3d thoracic, 1st, 2d, 3d, and 8th and 9th abdominal segments are 

 pale blue at the tips ; and sometimes those on a less number of segments 

 are tipped with blue. The six tubercles on the prothoracic segments are 

 still well developed. The suranal plate is pale red ; the sides of the 

 aual legs deep bright red, as also are the ends of the mid-abdominal 

 legs ; the thoracic legs are black ringed with red. 



Stage V. Length 65-70 mm. Head and body pea-green. Shape of 

 the body nearly as in Philosamia, but the tubercles very much thicker 

 and larger. Those on the 3d thoracic segment and 1st abdominal a 

 little larger than the pair on the 2d thoracic segment. The dorsal ab- 

 dominal tubercles somewhat unequal in size, those on segments 2-7 about 

 one-half smaller than those on the 1st abdominal segment, those ou seg- 

 ment G being a little smaller than the others. The median tubercle on 



