Veromessor Lobognathus in North Dakota (Hymenoptera: Formicidae)

In ,our field studies on the ants of North Dakota we have been in the habit of identifying our collections of Pogonomyrmex by casual inspection with the unaided eye. This seemed adequate, since there is only one species oi’ this genus in the state and since we knew of no other ant that could be confused with Pogonomyrmex. But after reading Gregg’s interesting paper2 on Veromessor we hurriedly re-examined our material under magnification. (See Fig. 1.). Among a hundr.ed nest-series of putative Pogonomyrmex occidentalis (Cresson) we discovered one o Veromessor lobognathus (Andrews). This is only the sixth collection .of this species, but it extends the range northward by 450 miles.. Since almost nothing is known about its habits and ecology we hoped that our field notes would contribute something, but we found them disappointingly laconic: "Under flat rock 32 x 2)x 2" lying on north wall of east-west valley. ATYPICAL." The word "atypical" is significant for it shows that at the time we regarded the ant as P. occidentalis and a Pogonomyrmex nest under a rock was something we had never seen. Our error was not detected until the autumn or winter of 1955. Consequently we could not return to the site until the summer of 1956. By that time southwestern North Dakota had suffered a year of drouth and ants (except P. occidentalis) were scarce and hard to find. We revisited the same hillside and literally "left no stone unturned"; in act we turned them over twice--the second time after the late summer rains. But we found no trace of the