560 PROCEEDINGS OF THE AMERICAN ACADEMY. 



segment, which are very slightly larger and longer than those on the 

 3d thoracic segment. The prothoracic dorsal tubercles each bear four 

 curved setae, while the 2d and 3d thoracic dorsal tubercles each carry 

 six setae. The abdominal tubercles are nearly as long as the thoracic 

 ones, but much slenderer, and they are rather high, contracting in diam- 

 eter in the middle ; they each bear 2 or 3 long curved black stiff bristles, 

 and two minute ones, the long ones being curved backwards, and before 

 the larva has begun to feed they are longer than the body is thick, so that 

 it appears to be rather thickly clothed with thie black bristles. 



The single median dorsal tubercle on the 8th abdominal segment is a 

 third thicker than the others in front, bearing three long black setae on 

 each side. 



The two dorsal tubercles on the 9th abdominal segment are quite large, 

 larger than those on abdominal segments 1-7. Two dorsal tubercles 

 arise from near the middle on each side of the suranal plate ; they are 

 ouly a third smaller than those on the 9th segment ; around the edge of 

 the suranal plate arise long grayish stiff straight hairs, and the bristles on 

 each lateral tubercle are grayish and directed downward. 



The body is dull straw-yellow on the sides and black above. The 

 wide black dorsal band is irregular in width, varying at the end of the 

 stage. 



It gives off on each side behind the middle a straight black rectangular 

 line forming a black half-ring extending down to near the spiracles; the 

 hinder edge of each segment is black. The color variations of the larva 

 in this stage are marked ; in the most extreme the entire upper part of 

 the body is black below the spiracles, the black pigment extending down 

 from the main mass to the infraspiracular tubercles, the under side only 

 of the body being yellow. There is low down on the side of the body 

 a narrow worn somewhat broken black line, situated below the infra- 

 spiracular tubercles. Spiracles small, inconspicuous, black. Thoracic 

 legs black; abdominal legs in general yellow, when freshly hatched black, 

 the planta slightly purplish livid. In this stage the larva is very pretty 

 and interesting, but with the true Saturnian shape of body and tubercles. 

 They moulted May 24 or 25. 



Stage 11. Length 12 mm.; toward end of stage 18 mm. Now very 

 different from Stage I. The body is pale straw-yellow, and no black 

 on it in my examples (while one of those reared by Mr. Joutel is black 

 on the sides and on the 1st, 3d thoracic and 8th abdominal segments, and 

 he found that there are all stages from the wholly yellow to the dark 

 form). 



