Comparisons of selected biological attributes were made to establish a phylogenetic basis for the classification of the Cicindela splendida Hentz group taxa. Recognized members of the group, C. splendida, C. limbalis Klug, and C. denverensis Casey, are spring-fall species, and northern populations emerge later during spring than southern populations. Despite differences in time of peak abundance, the three species overlap in time and space. The absence of large numbers of hybrids of these three species suggests that although closely related, their adults can distinguish from each other, and thus their rank as species should be retained.
Comparison of geographical distribution of these species with that of dominant soil types revealed that they had similar soil preferences. The geographical distribution of all three species was smaller than the range of their preferred soil types, probably because of the same factors that influence their local distributions.
Morphometric analyses of these species revealed a closer similarity between C. splendida and C. limbalis. In both sexes elytral pattern, percentage maculation, elytral colour, and non-sensory setae number collectively distinguish these species from each other, whereas body measurements, body ratios, sensory setae, and labral setae collectively fail to distinguish them.
Based on plesiomorph/apomorph character polarization, and the C. purpurea Olivier group as outgroup, it was determined that C. denverensis represents an early lineage of the C. splendida group, whereas C. splendida and C. limbalis are more recent sister species.
The ancestor of the C. splendida group probably evolved during late stages of the Tertiary Period as a North American resident and was a continental, riparian, cool-temperate form that ranged across Canada and northeastern and central United States. Extant forms speciated during the late Pleistocene as a result of spatial fragmentation of populations, isolation, and adaptation during glacial and interglacial periods.