Novel exocrine glands in the hindleg tarsi of the ant Nothomyrmecia macrops

The third tarsomere of the hindlegs of both workers and queens of Nothomyrm ecia macrops is almost entirely filled with a hitherto unknown exocrine gla nd (which does not occur in the closely related Myrmecia). Each of the appr oximately 30 secretory cells is connected to the outside via a duct cell. T hese open individually via large cuticular pores at the mesoventral side of the anterior part of the tarsomere. The diameter of the duct cells is narr ow near the secretory cell, but gradually increases towards their opening s ite. The rounded secretory cells show a well developed Golgi apparatus and numerous clear vesicles. The function of this gland is not yet known, altho ugh its opening site may be indicative of the deposition of marking substan ces. At the mediodistal side of tarsomeres 2, 3 and 4 in the three pairs of legs, a glandular thickening of the epidermal epithelium occurs; this repr esents another novel exocrine structure in ants. This epithelial gland occu rs in both Nothomyrmecia and Myrmecia.