374 REPORT 4, UNITED STATES ENTOMOLOGICAL COMMISSION. 



Aletias, there has not been a single Heliothis. In a warm fall the moths 

 have been known to issue during the month ot November j but whether 

 these individuals die or exceptionally hibernate is as yet an undecided 

 point. Our former statement (Third Missouri Entomological Eeport, p. 

 107*) as to the hibernation of moths was made after observations dur- 

 ing a late fall, when most of our specimens issued before winter, and we 

 erroneously took this exceptional occurrence for the rule. 



SUMMARY OF THE DISTINGUISHINa POINTS COMPARED WITH ALEXIA. 



The most salient points of difference between the Cotton Worm arid 

 the Boll Worm — those which will enable the planter to most readily 

 distinguish between the two insects at any stage of growth — may be 

 briefly summed up as follows : 



Egg. — The egg of the Aletia is of a delicate bluish-green color, while 

 that of the Heliothis is dirty white. Although the two eggs are of 

 about the same transverse diameter, the Aletia esg is very flat, while 

 that of Heliothis is conical, its longitudinal being equal to the transverse 

 diameter. Dr. Phares has neatly expressed the difference in shape by 

 likening the egg of Heliothis to an inverted tea-cup, and that of Aletia 

 to an inverted saucer. 



Larva. — The full-grown Boll Worm is somewhat longer and much 

 thicker than the full-grown Cotton Worm. It early loses the looping 

 method of locomotion, which to a certain extent persists throughout 

 life with Aletia. The reason for this is that the front pair of prolegs 

 (on the third abdominal joint) is well developed in Heliothis, while, as 

 we have already seen, it is atrophied in Aletia. The differences in 

 the normal markings are well shown upon the plates, yet certain of the 

 young Boll Worms so closely resemble Cotton Worms that some other 

 distinguishing character than that of stripes is needed. This character 

 is to be found in the piliferous tubercles on the back of both larvae. Of 

 these, in each species, there are four upon the upper side of each ab- 

 dominal joint. In Aletia these four spots form the corners of a rec- 

 tangle. In Heliothis, however, the posterior two are more widely sepa- 

 rated than the anterior pair, so that the four form a sort of trapezoid. 

 This character is absolutely constant. 



Pupa — The pupa of Heliothis is always found beneath the surface of 

 the ground ; that of Aletia is always above ground and usually inclosed 

 in a nest of silk and enveloped in a leaf. The pupa of Aletia is slender, 

 usually dark brown or almost black in color, and has a dull appearance. 

 The pupa of Heliothis, on the other hand, is stout, light brown in color, 

 and is smooth and shining. The abdomen of the i>upa of Aletia, as has 

 already been shown, is elongated and bears on its tip six delicate ex- 



*Most of the moths issue in the fall and hibernate as such, but some of them pass 

 the winter in the chrysalis state, and do not issue till the following spring. I have 

 known them to issue in this latitude (38^° north) after the Ist of Noyember, when no 

 frost had previously occurred, 



