236 HAROLD R. HAGAN 



free from the ootheca, it is able to rupture the membrane which 

 has now become too small for it. A longitudinal slit occurs over 

 the prothorax which is literally "popped" out through it. Ob- 

 servers of this phenomonon have uniformly described the humped 

 position of the embryo as the cause of the rupture of the cuticle. 

 My study has led me to the conclusion that we are dealing merely 

 with an attitude of the body as a result of the dorsal split in the 

 cuticle which permits the protrusion of the prothorax through 

 the opening. Continued movements, not only of the body 

 walls but also of the body fluids, force more and more of the 

 animal through this slit. The prothorax is greatly elongated 

 by this means and appears as a hump or loop over the head and 

 thorax. Alternating saw-like movements of the limbs soon 

 release the head and thoracic regions ; then the envelope is worked 

 backward off from the abdomen and the limbs are freed in suc- 

 cession. The abdomen is entirely uncovered before the tarsi 

 of the metathoracic legs. In thirty to fifty minutes after sus- 

 pension the nymph is running about actively and is approxi- 

 mately three times the length of the egg from which it hatched. 



