THE YOUNG BOLL-WORM. 299 



actual length of time between the laying of the egg and the time of 

 hatching, but it probably approximates to Aletia in this respect, although 

 the time may be somewhat longer. 



THE LAEVA. 



As just stated, we have disproved the old idea that by far the majority 

 of the eggs are laid upon calyx and involucre, and it consequently fol- 

 lows that the received opinions as to the newly hatched worm boring 

 immediately into the boll or flower-bud must also be thrown aside. The 

 worm after gnawing through its egg-shell makes its first meal upon the 

 part of the plant upon which the egg was laid, be it leaf, stem, or invo- 

 lucre. Should it be laid upon the leaf, as is usually the case, it may be 

 three days before the worm reaches the boll. Should they be laid upon 

 the involucre, the young worm bores into the boll at an earlier date. 

 Mr. Glover publishes what seems to be a phenomenal instance as the 

 normal one. He says : 



A boll- worm which was bred from an egg found upon the involucre or "ruffle" of a 

 flower-bud grew to rather more than a twentieth of an inch in length by the third day, 

 when it shed its skin, having eaten in the mean time nothing but the parenchyma, or 

 tender fleshy substance from the outside of the calyx. On the fifth day it pierced 

 through the outer calyx and commenced feeding inside. On the sixth day it again 

 shed its skin, and had increased to about the tenth of an inch in length. On the tenth 

 day it again shed its skin, ate the interior of the young flower-bud, and had grown 

 much larger. On the fourteenth day for the fourth time it shed its skin, attacked and 

 ate into a young boll, and had increased to thirteen-twentieths of an inch in length. 

 From this time it ate nothing but the inside of the boll, and on the twentieth day the 

 skin was again shed and it had grown to the length of an inch and one-tenth, but, 

 unfortunately, died before completing its final change. 



The extreme slowness of growth during the first six days is evidently 

 a mistake on the part of Mr. Glover in measurement, and, as such, should 

 here be corrected. He makes the larva at the end of six days and after 

 two molts one-tenth of an inch in length, whereas, according to our 

 measurement, it is usually nearly, if not quite, that length upon emerg- 

 ing from the egg, and at the end of six days has attained a very respect- 

 able size. The reason for quoting this paragraph was not only to call 

 attention to the mistake, but also to show the length of time which a 

 worm may, under certain circumstances, feed upon the outside of a boll 

 before piercing to the inside. As a rule, we may safely say that where 

 the egg is laid upon the involucre the worm pierces through within 

 twenty-four hours after hatching. 



The newly-hatched boll- worm walks like a geometrid larva or looper, 

 " a measuring- worm," as it is often called. This is easily explained by 

 the fact that, while in the full-grown worm the abdominal legs or pro- 

 legs are all nearly equal in length, in the newly-hatched worm the second 

 pair is slightly shorter than the third, and the first pair is shorter and 

 slenderer than the second, a state of things approaching that in the full- 

 grown cotton- worm, though the difference in size in the former case is 



