72 Ayinals Entomological Society oj America [Vol. XIII, 



but no recent accounts have been given of this fact in either 

 case. In Corydalis corniita there is an embryonic moh, but a 

 careful study of the same has not revealed any structure that 

 might serve as an egg burster. Furthermore, the process 

 of hatching gives no indication of the use of any such structure. 

 On the other hand, hatching is effected by a means none the 

 less interesting and perhaps unusual. 



When egg masses of Corydalis cornuta are cut or scraped 

 from their substratum, some eggs which are ready to hatch will 

 often hatch in a short time, so that hatching may be readily 

 observed. Frequently eggs that are ready to hatch, judging 

 from external appearances, may hold over for several days. 

 The hatching process proceeds rather slowly and varies in the 

 length of time between stages. Egg's ready to hatch are smoky 

 gray, often reddish or pinkish in the lower three-fourths and 

 lighter gray anteriorly. On the venter of the egg, the amber 

 colored bifid mandibles can be seen about one-third the distance 

 from the anterior end of the egg (Fig. 2). At the sides can be 

 plainly seen the two large black eye spots or ocellar fields, each 

 with seven ocelli. The head of the embryo is therefore bent 

 caudo-ventrad with the prothorax beneath the micropylar 

 area. 



Usually the first visible evidence of hatching is slight move- 

 ments of the embryo. Under highest power binocular, air 

 bubbles will be seen to be slowly going down the pharynx. 

 As this continues the anterior region of the egg becomes per- 

 ceptibly dilated. The chorion shrinks slightly as the air 

 within is withdrawn until it becomes rather closely appressed 

 to the embryo, suggesting premolting conditions. The contour 

 of the embryo can now be plainly seen, the large head being 

 very evident. The egg becomes asymetrical, due to the 

 enlargement anteriorly and the shrinkage around the abdomen 

 posteriorly. As the swallowing of air bubbles continues, the 

 embryo exerts considerable additional pressure by pushing 

 itself upward. The chorion over the anterior end of the egg 

 becomes tightly stretched under the increasing internal pressure 

 and finally gives way, providing the opening for the emergence 

 of the larva. The rent is usually small at first and difficult to 

 see, but soon increases to accommodate the large head of the 

 embryo. In no case did the mandibles pierce the chorion to 



