3 1 6 Bulletin American Museum of Natural History. [Vol. XXI , 



collect the sweet substance directly from these little insects. On 

 only one occasion have I been able to find a nest of plagiatus. While 

 walking on the summit of one of the Litchfield hills near Colebrook, 

 Conn., my attention was arrested by an unusually large number 

 of workers (about forty) of this species clustered about some aphides on 

 the lower surface of the leaves of a very young chestnut tree. I care- 

 fully followed the ants as they left the aphides in a straggling file and 

 descended the tree trunk. They ran over the twigs and dead leaves 

 and finally disappeared in a little depression in the ground about 

 eighteen inches from the base of the tree. This depression was so 

 well concealed under the dead leaves and twigs, that it would never 

 have been seen without following the foraging ants. It contained 

 between sixty and seventy workers, a number of worker larvae and 

 pupae and a few callows. Many of the ants, together with the green 

 leaves covered with aphides, were confined for a few days in an 

 artificial nest where they could be readily seen imbibing the drops of 

 sweet liquid from the anal openings of the plant -lice. When dis- 

 turbed the ants behaved like D. quadripunctatus ; that is, they crouched 

 with folded antennae in the depressions on the under sides of the 

 leaves. Careful search failed to reveal any other colony of D. plagiatus 

 in the neighborhood, and as I have never seen larger companies of 

 these ants whenever I have found them in other localities, I feel cer- 

 tain that they never form large colonies. In this respect plagiatus 

 resembles the European species, but though our American species 

 still retains the ancestral habit of seeking its food on trees and bushes, 

 it no longer nests in dead wood but in the soil. 



These habits are much more strikingly displayed by D. mar ice and 

 taschenbergi var. gagates. As these ants are among the most beautiful 

 and conspicuous inhabitants of that botanical and entomological para- 

 dise, the New Jersey pine-barrens, it is surprising that none of the 

 collectors who annually visit that region has taken the pains to observe 

 and publish an account of these insects. Both marice and gagates 

 are about equally abundant and, except in a few particulars, have 

 identical habits. The colonies are very large, comprising thousands 

 of individuals, and strictly monodomous — that is, restricted to a single 

 nest. The nest is excavated in the pure sand, nearly always about 

 the roots of the broom beard-grass (Andropogon scoparius) (Plates 

 XII and XIII) or of the liliaceous "turkey-beard" (Xerophyllum 

 setifolium), so characteristic of the pine-barrens; more rarely about 

 the roots of small bushes or in remnants of pine stumps. The work- 

 ers remove nearly every particle of sand from the roots and dig a 



