

ioo THE EMBRYOLOGY OF THE HONEY BEE 



reached the cephalic pole, and was expanded laterally to form 

 a pair of flat lobes, the procephalic lobes, rounded on their anterior 

 and lateral margins. At Stage VIII the germ band has lengthened 

 and its anterior end has now moved around the anterior pole of 

 the egg so that the procephalic lobes come to lie on its dorsal side 

 (Fig. Villi/). They are now no longer simple flat expansions of 

 the germ band, but are subdivided into two successive pairs of 

 lobes, an anterior and a posterior pair. The anterior pair, the 

 protocerebral lobes (iBr), are the larger, and in form and posi- 

 tion may be compared to a saddle, placed on the dorsal side of the 

 anterior end of the egg. Their lateral ends are rounded and 

 extend ventrad half way down the lateral surfaces of the egg. 

 The second pair, the deutocerebral lobes (2Br), which with refer- 

 ence to the embryo, lie caudad of the first, are situated just a 

 trifle dorsad of the cephalic pole of the egg, and are also saddle 

 shaped but are somewhat smaller, and their lateral margins, 

 instead of being broadly rounded converge on each side 

 toward small rounded elevations ; these elevations are the rudi- 

 ments of the antennae (Ant). In the mid-line of the embryo, 

 about half way between the protocerebral and deutocerebral lobes, 

 just dorsal to the cephalic pole of the egg, is a low elevation, 

 broad at its anterior (dorsal) end, narrow and cristate at its 

 posterior (ventral) end. This is the rudiment of the labntm 

 (Lm). Just below (caudad of) the labrum, at the cephalic pole 

 of the egg, is a shallow circular depression, the stomodacum, the 

 common rudiment of the mouth and oesophagus. Immediately 

 behind the mouth and near the mid-line are a pair of low rounded 

 swellings, the tritocerebral lobes (j-Br). Following these, but 

 nearer to the lateral margins of the germ band and in line with 

 the antennal rudiments are three successive pairs of low rounded 

 swellings. The first and largest of these are the rudiments of the 

 mandibles (Md), the next those of the first maxillae (iMx), and 

 the last those of the second maxillae (2Mx). These appendages 

 with the segments to which they belong, complete the head of the 

 future larva and imago ; the remainder of the germ band corres- 

 ponds to the trunk of the larva, and the thorax and abdomen of 

 the imago. On this portion of the germ band, destined to form 

 the trunk, eleven segments are plainly indicated in side view (Fig. 

 VHIb) by narrow intersegmental light zones alternating with 



