Most EcR²¹⁴/EcR^M554fs animals fail to survive to the second larval instar stage and few mutant animals survive to the 3rd larval instar stage. Homozygous larvae arrested prior to the second instar stage have both 1st and 2nd instar mouth hooks, while those arrested prior to the third instar stage have both 2nd and 3rd instar mouth hooks. The larval cuticle apolyzes and a large space appears between the cuticle and the epidermis at the anterior and posterior ends of the animal, although the tracheal trunks remain attached to the larval cuticle, in homozygotes that survive to the end of the third larval instar stage.