69a (68b).    Head and mouthparts prognathous (= directed forward), the head ca. as long along

                   midventral line as along middorsal line and usually cylindrical or a bit flattened ....…............70

 

 

69b.    Head and mouthparts hypognathous (= directed ventrally), the head much longer along

           middorsal line than along midventral line and usually rounded...........................………...................72