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