Key to the males of the Central American and Mexican species in the C. murinum species complex

1 Postpronotal lobe with patch or row of four or more well-defined setulae below prominent postpronotal setae (Fig. 12); gena more than half as wide as postpedicel (Costa Rica to Venezuela)................................ C. abrelatas sp. nov.

- Postpronotal lobe without patch or row of well-defined setulae below prominent postpronotal setae, although sometimes with 3–4 thin scattered setulae (Fig. 26); gena less than half as wide as postpedicel (Mexico to Venezuela)................... 2

2 Posterior margins of abdominal tergites heavily marked, markings covering most of tergite 3 (Fig. 51); arista with nine or more dorsal branches. Mexico to Costa Rica ............................................................ C. notatum

- Posterior margins of abdominal tergites weakly to moderately marked, markings sparse on posterior half of tergite 3; arista with 9 or less dorsal branches (Mexico to Venezuela)............................................................. 3

3 Male with inner lobe of surstylus very thin (10–15 times as long as wide), flat (Fig. 36); distal leaf-like lobe of distiphallus sclerotized medially (Fig. 39) (female unknown) (Mexico)..................................... C. prolixum sp. nov .

- Male with inner lobe of surstylus thin (6–8 times as long as wide), wedge shaped (Fig. 28); leaf-like lobe of distiphallus sclerotized on left side (female unknown) (Mexico to Venezuela).................................................... 4

4 Male with distal leaf-like lobe of distiphallus squat, asymmetrical; lower projection at base of lobe thin, sclerotized and reflexed (Fig. 31) (Mexico to Venezuela)............................................................ C. irksum sp. nov .

- Male with distal leaf-like lobe of distiphallus elongate, symmetrical; lower projection at base of lobe squat, membranous and folded (Fig. 46) (Mexico to Belize)........................................................ C. transitus sp. nov.