6 



It is of interest to note that the species was described from Europe 

 in 1796, while its lirst recorded occurrence in the United States was 

 in 1841. 



GENERAL APPEARANCE AND LIFE CYCLE. 



Throughout this bulletin the common appellation of this insect in 

 the cotton l:)elt, namel)^, the bollworm, is adhered to. It need hardl}^ 

 be explained that the larva known variously as the budworm of corn, 

 the tassel worm, corn earworm, and tomato fruitworm, is identical 

 with the cotton bollworm. 



The egg. — Bollworm eggs may easily be detected with the unaided 

 e3^e, and may be most readily found on the fresh silk of corn. 

 They are oval in shape, whitish or yellowish in color, and average in 

 diameter about 0.45™" to 0.5™"". Examined under a hand lens, they are 

 seen to be sculptured with polar ribs and cross furrows like those on the 

 eggs producing the cotton caterpillar. The eggs of this latter species, 

 however, are much flatter and greenish in color, and are, therefore, 

 not likely to be confused with those of the species under considera- 

 tion. The eggs of the bollworm hatch in from two and one-half to 

 six da3's, depending on the temperature. 



The larva. — The insect is most commonly known in this, the boll- 

 worm, stage. It is only during this larval existence that injury is 

 inflicted. Newlj^^ hatched bollworms are very small and are usually 

 quite overlooked by planters until the}^ are of suflicient size to attack 

 the buds, squares, and young bolls. As the larvae grow, a remarkable 

 diversity of color and markings may become apparent, ranging from 

 whitish or greenish without decided markings of any kind, to indi- 

 viduals which are rose colored or almost black, with distinct spots and 

 dorsal and lateral longitudinal stripes. This color variation has been 

 the source of some confusion as to the identity of the larva, particu- 

 larly when on other plants than cotton. The bollworm is a voracious 

 feeder and grows rapidly, completing its growth during summer in 

 from twelve to fifteen days. During the cool weather of spring and 

 fall its rate of growth is much slower. 



A full-grown larva measures from li to li inches in length. The 

 body is stout and tapers slightly toward the head and caudal extrem- 

 ities. In the darker individuals the markings consist of a narrow, 

 dorsal, central, longitudinal, black stripe, centered with a fine white 

 line. On each side of the bod}', including the breathing pores, is a 

 broad, whitish, lateral stripe, extending from the head to the last seg- 

 ment. Just above this lateral stripe is a broad, dusky, longitudinal 

 band, and between this latter and the central dorsal stripe is a broad 

 whitish band, often marked with fine whitish lines, but so delicate as 

 not to interfere with the general color of the body. On the more 

 central body segments are usually eight black spots, extending in an 



191 



