. The embryology of the honey bee. Honeybee; Bees. THE EMBRYOLOGY OF THE HONEY BEE 173. Fig. 67. Transverse section through the anterior half of the second maxillary segment of an embryo, Stage X, showing one of the pair of tracheal invaginations {Trlnv) and the mesoderm (Meso) belonging to this segment, x 387. clearly shown in figure Xa, but not labeled. At the beginning of Stage X the opening of the tracheal sac to the exterior has already- become contracted, and by the end of this stage or the beginning of the next (XI) is completely closed, leaving behind no trace of its existence. At the
. The embryology of the honey bee. Honeybee; Bees. THE EMBRYOLOGY OF THE HONEY BEE 173. Fig. 67. Transverse section through the anterior half of the second maxillary segment of an embryo, Stage X, showing one of the pair of tracheal invaginations {Trlnv) and the mesoderm (Meso) belonging to this segment, x 387. clearly shown in figure Xa, but not labeled. At the beginning of Stage X the opening of the tracheal sac to the exterior has already- become contracted, and by the end of this stage or the beginning of the next (XI) is completely closed, leaving behind no trace of its existence. At the same time the ectodermal folds also disap- pear, their disappearance being in part at least due to the shrink- age and withdrawal of the yolk from this region. The further history of the three remaining diverticula of each of the tracheal sacs remains to be considered. All of these elon- gate rapidly, assuming a tubular form. The dorsal diverticulum, which is the largest of the three (Fig. 68, ATraL), continues to extend dorsad, taking a slightly cephalad course, skirting the posterior margin of the cerebral lobes, along the line of junction of the head and trunk. At Stage XIII the distal ends of these branches reach the dorsal mid-line, when they unite to form the anterior tracheal loop or commissure (Figs. 63 and 64, ATraL). Of the two remaining diverticula the ventralmost forms the larger. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Nelson, James Allen. Princeton : Princeton University Press
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Keywords: ., bo, bookcentury1900, bookdecade1910, booksubjectbees, bookyear1915
