II 



ORGANIZATION OF THE EGG 



In form the egg of the bee approximates a long cylinder; one 

 end, however, being slightly larger than the other, and both 

 having a smoothly rounded hemispherical contour. The egg is 

 gently curved in its long axis, so that in profile one side is seen 

 to be decidedly convex, the other slightly concave (Fig. I). By 

 reflected light the egg appears pearly white, by transmitted light 

 it is seen to be translucent, with a saffron tinge. 



In length the eggs vary from about 1.53 mm. to 1.63 mm. 

 (0.059-0.063 inch). The larger end at its broadest point has an 

 average diameter of about 0.317 mm. (0.0122 inch), or approxi- 

 mately one-fifth of the total length. 



Both the differing size of the two ends and the marked bi- 

 lateral symmetry of the egg, expressed by the curvature of its 

 long axis are common among the eggs of insects in general and 

 always bear a direct and constant relation to the position of the 

 future embryo. In the egg of the honey bee, with reference to 

 the parts of the embryo, the larger of the two ends is cephalic 

 (anterior), the opposite caudal (posterior) ; the convex side, 

 ventral, the concave, dorsal. The position of the embryo is 

 therefore predetermined. Hence the terms cephalic pole, caudal 

 pole, dorsal and ventral sides may be applied directly to the egg 

 itself. A similar form and similar relations to the embryo are 

 possessed also by the ova of other Hymenoptera, for example 

 Formica (Ganin, 1869), Chalicodoma (Carriere and Burger, 

 1897), and Polistes (Marshall and Dernhehl, 1905). In many 

 other insects it is known, moreover, that the egg before deposi- 

 tion lies in the ovary of the mother in such a position that the 

 parts of the future embryo are directed or oriented coincidently 

 with those of the mother. That is, the cephalic pole of the egg 

 is turned toward the head of the mother. This is known as the 

 law of orientation of Hallez, named from its discoverer (1886). 



