STRUCTURE AND DEVELOPMENT OF EMBIA TEXANA. I 15 



line membrane is comparatively tough and separates from the 

 chorion in eggs kept in an alcoholic preservative. 



Unfortunately the youngest embryos were well advanced at 

 the time of preservation, being in an elongate fully-segmented 

 stage. As the embryo now extends over the whole of the de- 

 finitive dorsal surface with its head directed posteriorly, it prob- 

 ably attained this position by rotation, keeping at the surface of 

 the egg as in the Termites and not plunging through the yolk as 

 in the Orthoptera with elongate eggs. At this stage segmenta- 

 tion is nearly complete, only the posterior end being confused. 

 The antennas are short, borne by the rather large deutocerebrum 

 which shows a flexure around the posterior pole. The mouth 



FIG. 6. Three stages of the developing embryo, aw, amnion ; ant, antenna ; c/i, 

 chorion ; do, dorsal organ; far, labrum ; in, micropile ; md, mandible; vix l , . max- 

 illce, mxp, palpus ; ser, serosa, th^, 2 , 3 , legs ; z r . m, vitelline membrane. 



parts are large, single-jointed appendages, the labrum distinctly 

 bipartite. The head segments are nearly as strongly marked as 

 the thoracic. Of the limbs the first pair are slightly more ad- 

 vanced than the others. Whether this is due to the antero- 

 posterior direction of growth or to an acceleration of these im- 

 portant appendages would be hard to decide. The pleuropodia 

 are large, the remaining abdominal appendages are uniformly 

 smaller and disappear on the fifth segment. Beyond this segment 

 the abdomen curves into the yolk, while at the eighth segment 

 there is a sudden outward flexure. The " tail-piece " thus formed 

 is quite like the similar growth of Termes, etc. Sections of the 



