Key to third instar of Orphninae known larvae

1 Epipharynx without plegmatia and corypha not prominent; lacinia with 1 or 2 unci (never with 3 tips); posterior area of ligula with thin setae; anal slit sinuate ( Aegidiini) ................................................................2

– Epipharynx with plegmatia and corypha anteriorly prominent; lacinia with 3 unci (or 1 tridentate uncus); posterior area of ligula with stout setae, these setae are distinctly wider than anterior setae; anal slit Y-shaped ( Orphnini)...........................................................................3

2 Lacinia with 1 uncus; abdominal spiracles decreasing progressively in diameter posteriorly; metapretarsus with rounded and reduced apex (Mexico)............................................. Aegidium cribratum Bates,1887

– Lacinia with 2 unci (Figs. 31 -35); abdominal spiracles I-IV distinctly larger than V-VIII (Figs. 45-52); metapretarsus with well-developed and acuminated apex (Figs.38, 41) (Brazil) ......................................... .......................................... Paraegidium costalimai Vulcano et al., 1966

3 Surface of labrum without transverse carinae;stridulatory area of stipes with 14-15 acute teeth ......................................................................4

– Surface of labrum with two transverse carinae;stridulatory area of stipes with 20 acute teeth ( Hybalus) ............................................................ 5

4 Surface of labrum not trilobate and with small tubercles irregularly distributed (Italy)............... Chaetonyx robustus liguricus Mariani,1946

– Surface of labrum trilobate and without irregular distributed tubercles (Madagascar)................................. Triodontus nitidulus (Guérin,1844)

5 Clypeus with two externoclypeal setae; apex of galea with 2-3 setae distinctly larger than outer setae;hypopharyngeal sclerome tridentate (Italy)............................................................. H.benoiti Tournier,1864

– Clypeus with one externoclypeal seta;apex of galea with similar shaped setae;hypopharyngeal sclerome bidentate (Morocco)......................... .................................................................... H. rotrouni Petrovitz,1964