I 14 MELANDEK. 



EMBRYOLOGY. 



Daring the few weeks the Embias were kept in captivity the 

 females deposited a small number of eggs. These were laid dur- 

 ing the night-time, generally one at a time, and were often inse- 

 curely fastened to the surface of the jar by strands of silk. The 

 eggs, a dozen or so in number, were carefully preserved in hope 

 that the history of the embryos would give some clue as to the 

 systematic position of the family. 



The eggs are of a creamy-white color and of the retort-shape 

 noticed in So/ieri and Uhrichi, and possess a characteristic narrow 

 circular band of thickened chitin extending obliquely from the 

 apex of the narrower end to one third the distance along one 

 side. This structure is of great service in orienting the egg dur- 

 ing the later stages. In the ovaries of the female the eggs lie 

 with the narrowed end anteriorly and the oblique surface directed 

 upward and towards the median line of the body. Thus the primi- 

 tive ventral surface does not correspond with the definitive, but the 

 anterior end of the ovarian egg remains the anterior end for the 

 hatching embryo. The oblique circle outlined by the ridge is 

 doubtless detached at the time of hatching. The chorion is thin 

 but firm, and presents a smooth finely granular surface. Within 

 the circle, however, the surface is lightly roughened by trabeculae 

 and minute pillars, its alveolar structure corresponding with the en- 

 larged cells of the follicular epithelium. At the posterior median 

 point of the ridge is a small elliptical opening, the micropyle, 

 communicating with the irregular lumen of the ridge itself. This 

 opening is in connection with a smaller one passing into the in- 

 terior and provided with a grooved guideway. As in B/atta, no 

 gyration of the egg is necessary, during the passage down the 

 oviduct ; the micropylar opening comes directly in contact with 

 the mouth of the spermatheca, while the small size of the open- 

 ing limits the number of spermatozoa that find ingress. The 

 chorion is sometimes thin, due to imperfect secretion, and at 

 times is covered by the shed follicular epithelium. In this de- 

 tritus and among the strands of silk particles of soil adhere. 

 This might indicate that in the natural nests the eggs are con- 

 cealed for protective purposes by an added covering. The vitel- 



