270 REPORT OF THE COMMISSIONER OF AGRICULTURE. 



Wbeu a field is badly infested with cotton- worms tliey freqnenUy eat 

 tbe folded leaves containing pupae (Plate VII, figs. 8 and 9). Occasion- 

 ally such pupae remain susi)ended by their books and fragments of the 

 cocoon attached to the remains of the leaf (Plate YII, fig. 10). 



The duration of the pupa state varies greatly. During the warmer 

 part of tlie summer it is only six or seven days, but in the autumn indi- 

 viduals of this species have been known to remain a month in this state. 



The adult. — The size and appearance of the adult are represented on 

 Plate VII, figs. 11, 12, 13. The general color of the upper surface of the 

 wings and body is light brown. The anterior wings are tinged with 

 wine-color on the inner and middle parts, shading into a light olive- 

 green on the external portions. These wings are marked by several 

 wavy transverse lines of a reddish color, and by a black or grayish spot 

 near the center of each wing; outer border fi-inged with white, with six 

 reddish, spots. These characters vv^ill serve to distingiiisl; this insect, 

 but a more detailed description is appended to this section. 



Unlike the larva, the RdnltAletia argillacca is not confined to a single 

 article of food, the moths feeding upon sweets of many kinds. Although 

 nectar forjns a considerable part of this food, the moths seldom visit 

 flowers for this substance. A few plants possess nectar glands in addi- 

 tion to those of the flowers, and it is from such plants that these moths 

 obtain nectar. The cotton plant is one of this number, each leaf being 

 furnished with from one to three nectar-secreting glands. Usually thiere 

 is but one of these, which is situated on the lower surface of the main 

 rib, near the petiole (Plate VII, fig. 14) ; occasionally leaves can be found 

 in which ea(?h of the three larger ribs is furnished with a gland. This 

 gland appears to the naked eye as a swelling of the rib, in the 

 center of which is a depression containing usually a drop of clear, some- 

 what viscid, sweet fluid. ^Vhen this fluid is not consumed by moths, 

 ants, or other insects it vnll accumidate so as to form a large drop pro- 

 jecting beyond the walls of the gland. Other glands, similar in appear- 

 ance and function, are situated, one at the base of each of the three bracts 

 forming the involucre or " square," and sometimes also three additional 

 glands at the bottom of the calyx alternating with these bracts. 



While in the field, during the summer of 1878, 1 became interested in 

 these facts, which I afterwards learned had been observed long before 

 by Professor Glover. When I informed Professor Eiley of certaiu obser- 

 vations that I had made, he suggested that perhaps the cotton-moth 

 also derived nourishment from these glands. Subsequently, a.t Bacon- 

 ton, we, in company with Professor Willet, went into the field at night 

 with dark-lanterns to study this subject. Within a half hour from the 

 time we entered the field, I had the pleasure of pointing out to Professor 

 Kiley a moth in the act of sipping nectar from a gland at the base of a 

 boll ; thus proving the truth of his inference. We also observed moths 

 feeding at the heads of Paspalum leave, a common grass gTowing as a 

 weed in the cotton fields. Although no other\ioths were observed at 

 that time to feed on the nectar of cotton, during the present season (1879) 

 many observations have been made showing that it is the normal habit 

 of this insect to do so. A few days after the discovery of the moth feed- 

 ing at the extra-floral nectar glands of the cotton, my host. Captain 

 Bacon, informed me that as he was riding home in the evening from a 

 distant part of his plantation he observed a large number of moths fly- 

 ing about some cow-pea vines that were growing in a corn-field. I at 

 once equipped nivself with a lantern and proceeded to the corn-field. On 

 ar]i\ii!g tiicre 1 v/itnessed a remarkable sight; thousands of the cotton- 

 moths were about the pea- vines feeding on the nectar excreted by a 



