ANTS VS. COTTON-WORMS. 185 



red ant, yet I never saw ants attack them on the plant excepting when I had thus 

 placed them on ridge-cotton for purposes of study ; but when creeping over the ground, 

 as they do after eating up the foliage of the plant on which they were born, if not full 

 grown, hundreds of caterpillars were attacked by these ants and killed. I have never 

 seen more than one species of ant attacking any individual caterpillar, either on the 

 plant or on the ground. 



Mr. Trelease further remarks, in speaking of the enemies of the chrysalis : 



In the latter part of July several Aletia, just about to pupate, were taken from the 

 swamp where they were found, and, with leaves webbed about them, they were trans- 

 ferred to cotton on dry soil near the house, where they were tied by their leaves to 

 the petioles of this cotton; my object in placing them there being to determine the 

 length of the pupa state. The same day they shed their last larva skins and this left 

 them in an almost defenseless condition till the pupa skin should become firm and 

 tough. About twenty-four hours after this moult they were again visited, and were 

 found covered with red ants, which had killed and partly eaten them all, though they 

 were on different plants, and care was taken to see that there were no ants on the cot- 

 ton when the larvae were placed there. 



Concerning the destruction of eggs by ants he has made no positive observations, but 

 states his opiuion in the following words: 



Similarly, ants of quite a number of species frequent the cotton plant, whither they 

 are attracted both by the sweet excretion of Aphides and by the nectar copiously ex- 

 creted from the foliar and involucral glands of the plant, and although I never saw 

 them molest the eggs of Aletia, I believe that they do so. 



Family FOKMICIDAE. 



Ants without a sting. A single node upon the petiole. No contraction after the 

 first joint of the abdomen proper. The nymphs sometimes inclosed within cocoons, 

 sometimes naked. 



Sub-family DOLICHODERIDAE, Forel. 



Zoit. fur wiss. Zool., xxx, supl., and Etudes Myrmecologiques, Bull. Soc. Vaudoise, Sci. Natur, 

 1878, p. 364. 



Pedicel with a single node. The abdomen is not narrowed after its first segment. 

 Nymphs always naked. Nests commonly made in the ground. Antennae 12 joints. 



Genus DORYMYRMEX, Mayr. 



The maxillary palps 6-jointed, the labial palps 4-joiuted. The shield a little pro- 

 longed between the insertions of the antennae. The clypeal fosse is united to the an- 

 tennal fosse. The frontal area is triangular, short but distinct. The scale of the 

 petiole vertical, smooth. The chitinous skin elastic. All the spurs pectinated. The 

 workers have nearly always a tuft of long hairs under the head, as in the genus Pogo- 

 noinyrinex. The mesothorax is a little compressed. There is a cone or toothed pro- 

 jection between the posterior or basal face and the anterior face of the metanotum. 

 The spurs are pectinated. Ocelli are wanting. 



No. 1. D. insanus, [Buckley]. 



1866. Formica insana [Buckley], Trans. Am. Entom. Society Philadelphia, p. 165. 

 1866. Erratic ant, Lincecum, Proc. Acad. Nat. Sci. Phila., p. . 

 1875. Dorymyrmex pyramicus, Korton, "Wheeler's Hep. Geo. Expl., Zool., p. 734. 

 1879. Dorymyrmex insanus |McCookj, Agricultural Ant of Texas, p. 197. 



This species may prove to be D. pyramicus, Rog. (Prenolepis pyramica), as suggested 

 by Norton, or more probably a variety of the same. 

 Buckley's description is sufficiently indefinite, but two examples of his types in the 



