Key to Tridactylidae species in the Southeastern United States
* Note: There are two recently described species of Tridactylids ( Ellipes eisneri Deyrup and Neotridactylus archboldi) Deyrup and Eisner) known only xeric sandy uplands in Florida. These species have reduced wings, and appear to be flightless. They will be incorporated into the key soon. It may be possible that these or other flightless species occur in similar situation throughout the South.
| 1. Hind tibia with two swiming plates and hind tarsi absent (Fig.1), smaller species..............................................Ellipes minuta (Scudder) | 1'. Hind tibea with four swimming plates, and hind tiba present, though one segmented. Larger species ..............................................Neotridactylus apicialis (Say) |
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| Fig. 1: Hind tibia of E. minuta showing two swimming plates, and lack of hind tarsi. | Fig. 2: Hind tibia of N. apicialis showing 4 swimming plates |
