A REVISIONARY STUDY OF PHEIDOLE VASLITI PERGANDE (HYMENOPTERA: FORMICIDAE)

Abstract

During the period from 1950 to 1953 the writer observed a large number of colonies belonging to the vasliti complex in southern Arizona and Mexico. Samples from these colonies brought home for further study have indicated that the existing taxonomie structure of the complex is not altogether satisfactory. Much of this trouble results from the variable color of these in? sects, which cannot be correlated with distribution or even with differences in nest sites. But after it had been determined that the named color varieties in this complex have no distributional significance, a serious difficulty still remained. This is the exact nature of Pergande's species vasliti. As is shown in this study, Pergande had a very hazy concept of the character of vasliti. It is not surprising, therefore, that those who later worked with this insect based their ideas of vas? liti on something more tangible, notably Forel's variety hirtula. This procedure was not entirely unfortunate, for it can be shown that hirtula is a sound species in its own right. Indeed, there is room for the view that the status of hirtula has been too sound. Because it is so distinct and so easily recognized, hirtula has carried the unrecognizable vasliti on its back for nearly sixty years without anyone appreciating the drastic shortcomings of the latter species. It is evident that Forel (1899) believed that he could recognize vasliti, for he described hirtula as a variety of it. But Forel did not know that the worker caste of hirtula is polymorphic until Wheeler sent him nest series from Quere taro in 1900. Forel then realized that the insect which he had previously treated as Pergande's obtusospinosa is actually the major of hirtula. Then Forel (1901) took characteristic action ?he protected his variety hirtula by declaring that obtusospinosa is the major worker of vasliti. In a few years this mistake was recognized and corrected, but Forel's equally mistaken conten? tion that hirtula is a variety of vasliti has been accepted without question to the present.