A New Character for the Identification of the Boll Weevil and the Thurberia Weevil (Coleoptera: Curculionidae)1

Abstract

The criteria given by Pierce (1913) for distinguishing the thurberia weevil ( Anthonomus grandis thurberiae Pierce) from the boll weevil ( Anthonomus grandis Boheman) have proven satisfactory when one confines his identifications to the populations that these criteria were meant to distinguish. One's identifications are doubly certain if he is dealing with the principal populations of the two. The boll weevil ranges all over the southeastern United States but is not known from west of Texas. The thurberia weevil is confined to Arizona in the United States. However, when one attempts to apply Pierce's criteria to the identification of unknown populations, he experiences some difficulty. Some boll weevils look very much like thurberia weevils and thurberia weevils sometimes look like boll weevils. Average differences may exist but it is not easy to compare samples on average differences alone. Any extension of the range of either weevil into new territory could have serious economic implications. If one has only a small sample for identification, it is easy to wish that someone else had to make the decision.