90 REPORT 4, UNITED STATES ENTOMOLOGICAL* COMMISSION. 
ants occupied in destroying the eggs of Aletia, or still more frequently 
in attacking the young worms that are helpless while in the act of molt- 
ing, or in devouring the interior of the still more helpless chrysalides. 
Even old worms which, from cause whatsoever, once get to the ground, 
aro almost sure to fall a prey to these persistent and voracious little 
animals; the writhings, jerkings, and jumpings of the worm being of 
no avail against the constantly increasing numbers of the enemy that 
come to the attack. Attractive as is the honey from the glands of the 
cotton plant to the Cotton Moth, it seems to attract few other insects, and 
even the ants, that have such a predilection for sweets, are only oc- 
casionally found partaking of it. The universal presence of ants on the 
cotton plants, and of their nests in the ground at the base of the plants, 
seems largely due to the similarly universal presence of the cotton plant- 
lice. 
The ants are always to be seen busily occupied in obtaining sweets 
from these Aphides, while but few are noticed to be sucking the liquid 
secreted by the glands. Xow the plant- lice rapidly decrease in number 
with the advance of hot weather, though they never disappear entirely 
from the plants. The ants, as summer advances, are thus deprived of 
a large portion of their principal food supply, and as their colonies be- 
come more and more numerous with the progress of the season, they 
are obliged to seek other food. It is but natural, therefore, that they 
should fall to preying on the Cotton Worm. It has already been men- 
tioned that rains hinder the working of the ants, and that storms 
destroy them. They will, therefore, prove most effectual in assisting 
man where they are most protected from heavy showers, as on new 
laud where the soil is uneven, or in fields where there are stumps, 
trees, &c. 
To Mr. Trelease the work of the ants seemed so important as to sug- 
gest the possibility that the nectar glands of the cotton plants were 
originally developed by natural selection for the purpose of attracting 
ants which should act as protectors against the attacks of Aletia or 
some other enemy. 
The species actually observed destroying the cotton worm have either 
been determined or described by Rev. H. C. McCook, and are as follows : 
Dorymyrmex insanm (Buckley), D. flavus McCook (variety of imanus), 
Iridomyrmex mcwcooki, Sotenopsis xyhni McCook (=$.geminata Fabr.), 
and Monomorium carbonarium Smith. In addition to these, Cremasto- 
gaster lineolata Say and C. clara Mayr are found nesting in the cotton 
fields and may be safely counted among the enemies. For descriptions 
of these species see note "\ 
The most common and effective species in the Southwest is the Sole* 
nopsis geminata Fabr., a small species (Fig. 10) averaging 2.8 mm in length, 
and of a pale fuscous color, with a darker, piceous abdomen. 
Among the Dorylidre (a family closely related to the ants and consid- 
ered by some as belonging to them) we have found Labidus harrisii 
