74 PROCEEDINGS OF THE AMERICAN ACADEMY 



2. Disappearance in Stage III. of the transverse black bands. The 

 abdominal tubercles all become blackish. 



3. In Stage IV. the head becomes yellow, being less conspicuously 

 marked, and the dorsal abdominal tubercles are about half as long and 

 large as those on the 2d and 3d thoracic segments. 



4. The body becomes in the last stage much smoother than before, 

 the dorsal prothoracic and abdominal tubercles being much shorter 

 than in Stage IV. This reduction of size and inconspicuousness of the 

 dorsal abdominal tubercles is carried out to excess in 0. angulifera, 

 where they become obsolete, and the larva is simply a large green 

 caterpillar with inconspicuous markings, and simply protected by its 

 green color, like the majority of lepidopterous larvae ; not being so 

 strikingly marked as in the fully fed Samia cyrithia. 



The Life History of Samia cvnthia (Drury). 



The eggs were received from Mr. H. Meeske. The larva? were at 

 first fed on the leaves of the ailanthus, but wheu transferred to Bruns- 

 wick, Maine, ate freely of the wild plum. 



The Egg. — Regularly oval-cylindrical, dull chalky white ; the sur- 

 face of the shell finely pitted, but not arranged in wavy rows as in 

 P. cecropia ; the pits under a half-inch objective are near together and 

 slightly polygonal, and their walls project as little bosses on the inside 

 of the shell. Length 2 mm., thickness 1.4 mm. 



Larva, Stage I. — Hatched June 1 1 . Described one day after 

 hatching. Length 4—5 mm. Head rather large, as wide as the pro- 

 thoracic segment. The body gradually tapers from the head to the tail, 

 and is of a pale greenish yellow, the head dark chestnut, with a pale 

 greenish clypeus and labrum. The prothoracic segment is broad and 

 somewhat flattened above, with a dark chestnut-colored chitinous plate 

 or squarish patch on each side, sometimes appearing as widely separated 

 by a pale greenish yellow clear median dorsal space ; with four dorsal 

 and two lateral black tubercles ; of the dorsal ones the two in the 

 middle are slightly larger than those outside, and larger than the lat- 

 eral one-; ; they are also connected at their base by a slight ridge. All 

 the tubercles are much alike on all the segments, bearing from 5 to 7 

 seta?, those on abdominal segments 5 to 7 scarcely smaller than those 

 on the thoracic. The hairs or bristles are whitish, or rather colorless, 

 4 or 5 to 7 on each dorsal tubercle ; they are slender, not stiff or 

 thickened at base, and are spinulated, the spinules short and acute; 

 under a half-inch objective they appear, not bulbous, but tapering, and 

 being transparent may be glandular. 



