84 KEPORT UPON COTTON INSECTS. 



will serve to distinguish this insect, but a more detailed description is 

 appended to this section. 



Unlike the larva, the adult Aletia argillacea is not confined to a single 

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

 nectar forms 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 there 

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

 rib, near the petiole ; occasionally leaves can be found in which each 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 depres- 

 sion containing usually a drop of clear, somewhat viscid, sweet fluid. 

 When this fluid is not consumed by moths, ants, or other insects, it will 

 accumulate so as to form a large drop projecting beyond the walls of 

 the gland. Other glands, similar in appearance and function, are situ- 

 ated, 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. 



These glands were first figured by Professor Glover in his manuscript 

 work on cotton. The leaf-gland is represented on Plate IX of that work, 

 accompanied by the statement : " This is frequently tilled with a sweet 

 substance which proves very attractive to ants and other insects." The 

 glands of the involucre are represented on at least six different plates j 

 and on Plate XX especial attention is called to them. The explanation 

 of the plate reads as follows : " One of the three glands on the outside 

 of the involucre secreting a sweet, viscid substance much sought after 

 by flies, ants, &c. This gland is sometimes pierced by insects, causing 

 a different kind of rot." 



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

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

 by Professor Glover. When I informed Professor Riley of certain obser- 

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

 also derived nourishment from these glands. Subsequently, at 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 

 Riley 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 Paspalnm here, a common grass growing as a 

 weed in the cotton fields. Although no other moths 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 



