5T 



less as a transition to the third type, which is pink or rose colored. 

 The dorsal color pattern in a dark tj^pe of larva is shown in Plate VI, 

 figure 4. 



DESCRIPTIONS OF INSTARS. 



Following are the detailed descriptions of the different stages of a 

 generalized larva. ^ No reference is made to the color variations or to 

 slight individual differences shown in the specimen at hand: 



Stage I. 



At exclusion from the egg the tubercle areas are pale and the cervical shield 

 characteristically crescent-shaped, its posterior margin regularly convex, the anterior 

 margin concave on each side and acutely produced medially. Shortly afterwards both 

 become normal for instar I. 



Millimeters. 



Average length at hatching 1.5 



Average length before ecdysis 3. 8 



Average width of head cast 3 



" Semi-looper. " Body slender; pale translucent, yellowish in certain lights; 

 greenish after feeding. Surface minutely hairy. Head much larger than the follow- 

 ing segments, cordate; shining black, bearing many setae. Mouth parts, ocellar 

 spots, and antennae pale. Cervical shield shining black, sometimes paler, bearing 

 eight small tubercles arranged in two rows of four each; shape broad, peltate, the 

 anterior and posterior margins emarginate or sinuate, the sides oblique. Anal shield 

 dilute black, quadrate, emarginate behind; bearing eight small tubercles. Legs 

 dusky, furnished with many stiff setae. Prolegs pale, their shields quadrate, dilute 

 black, the latter being in reality the blackened area surrounding tubercle vii; the 

 anal pair with an inverted V-shaped dusky marking on the lateral aspect; the two 

 anterior pairs shorter than the others, first one-half as long as third and fourth and 

 the second slightly shorter than the third and fourth. Spiracles inconspicuous, 

 black. Body beneath pale, the ventral nerve ganglia showing through as single 

 round orange spots on segments I to X. 



Tubercles minute, situated in large irregularly circular dusky areas which are 

 absent in the larva directly after exclusion frOm the egg. Tubercles arranged as 

 follows: 



Segment I : i-viii placed in two rows of four each above and in front of the spiracle. 



Segment II: Ten tubercles in a transverse row across the segment, the line curv- 

 ing forward; i smallest, ii largest, twice the size of the next smaller and equal to v. 

 A single tubercle above and behind the leg. 



Segment III: Arrangement the same; i smaller than i of preceding segment and vi 

 farther back. 



Segment IV: i, ii, iii, and iv, circular, equal; seen from above i and ii form a trape- 

 zoid; i slightly larger than ii; seen from the side iii, iv, and v form a triangle 

 surrounding the spiracle, iv in the stigmatal stripe; vi absent; vii and viii minute, in a 

 transverse row. 



Segment V: Arrangement the same; vii and viii in a triangular group on the 

 venter, the first or outer of vii largest. 



« Combined from a series of twelve bollworms hatching from eggs laid by the 

 same moth and reared under identical conditions. 



