PROCEEDINGS, 1917. 45 



came mature and was ready to enter the ground by the middle of August and in less 

 than a month the adults emerged to lay the eggs of the second generation. In this 

 brood the larval periods are somewhat longer, and the winter is passed in the pupal 

 stage. 



THE EGG 



The eggs are laid in flat masses of from 150 to 500 per mass, closely contiguous; 

 a single egg is .65mm. in diameter, spherical, slightly flattened on top and base; sur- 

 face coarsely ribbed, the ribs being divided by rows of circular punctures. Color when 

 first laid pale green, an irregular purple spot appears in the centre of the cap about two 

 days later and shortly before batching the whole egg turns purple. 



THE LARVA. 



The larvae in emerging ate through the cap increasing the size of the hole until it 

 was large enough to permit escape. After emerging the tiny larvae fed first on the 

 empty egg shells, generally consuming them entirely before starting to feed on the plant. 

 The larvae were gregarious in habit in the early stages, at first only skeletonizing the 

 leaves, but later, as they became larger and separated, the entire leaf was devoured with 

 the exception of the midrib and larger veins. The very young larvae would spin down 

 by a silken thread when disturbed, but this habit was soon lost as the weight of the 

 caterpillar increased, and then their only protection was to curl up in a tight ball and 

 fall to the ground, later re-ascending the plant by the stem. The larvae passed through 

 a series of five moults, the last one taking place after the cocoon had been made in the 

 ground. 



DESCRIPTION OF INSTARS. 



First instar. — The larvae when first hatched measure 1.89mm. -2. 26mm. in 

 length. Head .36mm. -.38mm. wide. Body dark greenish yellow in color bearing numer- 

 ous black setigerous warts or tubercles. Head, prothoracic shield, and anal plate black. 

 True legs and prolegs black. After feeding the general body color becomes a lighter 

 greenish yellow. Duration of the first instar eight to ten days in the first brood, five to 

 seven in the second. 



Second Instar. — The larvae measure 4.3 mm. -4. 5 mm. in length when newly 

 moulted. Head .65mm.-. 75mm. wide, color brown; prothoracic shield yellowish gray 

 bearing four setigerous warts or tubercles. A short transverse black line occurs at base 

 of shield. A broad black median stripe runs longitudinally over the dorsum, divided 

 by a very narrow white line almost disappearing over the last three abdominal seg- 

 ments. Laterad of the median black stripe there is a narrower yellow stripe bearing a 

 black setigerous wart on each segment, a narrow black stripe, an irregular white stripe 

 bearing numerous round black marl ings, a blac' ish gray stripe, and a wide yellow 

 stripe. The lateral surfaces bear numerous irregularly placed setigerous warts. The 

 ventral surface is a light slate color. Thoracic legs black. Prolegs concolorous with the 

 ventral surface. Duration of the first instar four to six days in the first brood, five to six 

 in the second. 



Third instar. — The larvae measure 10mm. 12mm. in length when newly moulted. 

 Head .96mm.-1.18mm. wide, brownish black in color, beset with a few fine short setae. 

 Prothoracic shield bluish gray with irregular black markings. The narrow white stripe 

 dividing the broad black dorsal stripe is more broken than in previous instar and of a 

 bluish shade. The adjacent yellow stripe is broader and the row of black warts in the 

 centre are beset with black setae. The irregular white stripe is very broken, of a dis- 

 tinct blue shade. Ventral surface whitish yellow. All other markings, tubercles, etc. 

 similar to previous instar. Duration of the third instar five to eight days in the first 

 brood, eleven to thirteen in the second. 



