Larval mouthparts of C. atrella
a. Pecten epipharyngis with teeth of type B; b. Antenna - note long, narrow basal segment;
c. Mentum - note 4th laterals slightly reduced;
d. Ventromentum with relatively wide anterior margin (VMR about 0.33); and 40-50 striae
e. Mandible - note 3rd inner tooth separated (not usually to extent seen here) and partly darkened (type IIB).