REPOKT OF THE ENTOMOLOGIST. 337 



line; down the center of the back is another dusky line, or stripe, as it 

 should preferably be called; this dorsal stripe has a naiTow white line 

 down its center, and it is bordered on each side by a narrow white line. 

 Between the dusky dorsal and lateral stripes run four or five very faint, 

 wavy, longitudinal, white lines, so faint as not to interfere with the gen- 

 eral color of the body. Each body-ring has eight black s])Ots, which, 

 upon being examined with a lens, are seen to be tubercles, each with a 

 stiff hair upon its tip. These spots are arranged in two transverse rows of 

 four, the spots in the front row being slightly closer together than those 

 in the back row; the outer spot of the back row is small and placed 

 nearer the front row. 



Of these features the most constant seems to be the whitish stripe on 

 each side. When the boll- worm is brown these strijies assume a yellow- 

 ish hue. They are shown in all illustrations of the bolLworm yet pub- 

 lished, and are present in all sxtecimens in the department collection. 

 Another pretty constant feature is the relative position of the tubercles 

 just described. They are not always of a contrasting color to the rest 

 of the back, and hence cannot always be spoken of as spots. When 

 they are not discernible as spots, however, an examination with the lens 

 shows them still present as tubercles, each surmounted by a hair. This 

 point affords apparently a good and reliable means of distinguishing the 

 young boll-worm from the young cotton-worm, which otherwise might 

 prove a matter of difficulty during the earlier stages and in the early 

 part of the year, before black cotton-worms arQ to be found. In the 

 cotton- worm the two middle spots of each of the two rows of four are of 

 the same distance apart, so as to form the four corners of a rectangle. 

 In the boll-worm, however, the two middle spots of the hind row are 

 more widely separated than the corresponding spots of the front row. 

 This distinction may be recognized at a glance when the eye has become 

 accustomed to it. The dusky dorsal stripe is often wanting, as also are 

 the dusky lateral stripes, and, as just stated, the spots are often indis- 

 cernible. 



Mrs. Treat seems to have noticed a untformity of color as between 

 individuals of the same brood, and a diversity as between those of dif- 

 ferent broods. She says : 



I did not tliink that this gre«n larva that eats into the pease and stalks of corn, be- 

 fore the latter are half growu, was, aa you inform me, this same striped boll-worm 

 that eats into the cars of corn. » * • 



Such uniformity depending upon brood, or diversity from diversity 

 of brood or food-plant, can by no means be laid down as a rule. The 

 early brood, however, seems to consist almt>st entirely of green individ- 

 uals, and those feeding ui)on other i)lants than corn and cottou are more 

 usually green also. The pink individuals are more common upon (jottou 

 and the roasting-ears of corn. As Mrs. Treat has stated, a green worm 

 may turn brownish after the later molts, but half -grown brown worms 

 are very abundant in the bolls of cotton. In this connection, Mr. Glover 

 states : 



These variations of color are noteasily accounted for, as several caterpilbrs changed 

 color without any apparent cause, hoiug fed upon the same food and in the same box 

 with olihers. Several planters assert that in fchs earlier part of the sea.'ion, the green 

 worms are ^'onud in the greatest number, whila t!ie dark brovru varieties are"seen 

 later in the autumn, as we know is also the case wir.h the caterpillars of the cottou- 

 worm. 



We have shown elsewhere that the larva olEeliotMs has one redeeming 

 character in its occasional cannibalistic and prcdaceous turn of mind. 

 Boll-worms, when in confinement, iuive the habit, in common with other 

 22 AG 



