Knowltonia calida Knull, new combination

Knowltonia calida (Knull), new combination and status

(Figs. 1, 7)

Chrysobothris biramosa calida Knull, 1958:96; Nelson, 1960:73 (callida, sic); 1962:59 (callida, sic). Chrysobothris atrifasciata: Nelson, 1959:24 (misidentification); 1966:39 (part; misidentification).

Considering that the distinctive general structure of the male antennae is diagnostic for the genus, we feel that the highly asymmetrical rami of the male antennomeres 4-11 in this taxon warrant species, rather than subspecies, distinction. This species appears to be restricted to the Colorado Desert of SW Arizona, SE California, extending into Baja California (Norte) and, possibly, Baja California Sur, Mexico. Although the few specimens we have seen from the latter state come closest to K. calida based on the male antennae, nevertheless there are differences, and much more material for study is needed from the peninsula.

Knull (1958) distinguished this taxon from “typical C. biramosa ” only by its dorsal green color. He made no mention of any other difference, and it is strange he overlooked the antennal character. The color no longer works well as a diagnostic character, though K. calida is uniformly deep green, sometimes with a bluish cast, while green forms of K. biramosa are lighter green, often with coppery reflections that are more notable at the base of the elytra.

This species has been collected on Atriplex lentiformis (Nelson, 1959; 1962; 1966) and A. canescens (Nelson, 1960). Barr and Westcott’s (1976) treatment for this species should instead refer to K. biramosa.