NOTES AND MEMORANDA. 143 



pad of Camponotidce, pierces tte tunica propria of the bladder, losing 

 its own tunica propria, and, pushing the intima before it, hangs free 

 in the cavity, either as a twisted tube with a knob at the end — 

 whence the name of this type of apparatus — or as a mere knob : in 

 either case the whole intra-vesicular portion of the gland is invested 

 by the invaginated intima of the bladder, which takes the place 

 of the tunica propria. At the extremity of the knob is the 

 aperture by which the gland opens into the bladder, and at which the 

 in-turned intima of the latter becomes continuous with the true 

 intima of the gland. The protoplasm of the gland exhibits no cell 

 contours, but only nuclei imbedded in granular protoplasm, the latter 

 being pierced by the fine chitinous offshoots of the intima of the 

 gland. The knob is made of an accumulation of cells, also with 

 chitinous tubules. 



In connection with both types of poison apparatus are found 

 accessory glands (Nehendrusen) lying towards the ventral side of the 

 poison-bladder, and answering to the oil-gland of bees and other 

 Hymenoptera. They are unpaired glands, opening by a duct imme- 

 diately below the opening of the poison-bladder, and may be either 

 simple or bilobed. The wall consists of five layers, an intima 

 bounding the large cavity, a layer of polygonal epithelial cells, one of 

 scattered nuclei, a tjmica propria, and a network of fine muscular 

 fibres. The secretion is oily and of a yellowish colour. 



The anal glands and anal bladders are stated to have been 

 hitherto overlooked in ants ; they are formed by an infolding of the 

 wall of the cloaca between the anus and the pygidium or last out- 

 wardly visible tergum. The bladders are two large ovoidal sacs closely 

 applied to one another in the middle line, and uniting posteriorly 

 into a small ampulla from which proceeds the short duct ; their walls 

 consist of an intima, a delicate protoplasmic matrix with scattered 

 nuclei, a tunica propria, and a network of muscles. The glands are 

 also two in nvimber, and each is closely applied to the outer wall of 

 the corresponding bladder, into which its duct opens by a large 

 funnel-shaped aperture. The gland-cells are large and spherical, 

 and very easily separated from one another ; each contains a large 

 nucleus with many nucleoli, and is suji plied with a special tracheal 

 branch. The duct of the gland gives off fine lateral offshoots, one of 

 which proceeds to each gland-cell : on reaching the cell its protoplasmic 

 outer layer becomes continuous with the cell-membrane, while its 

 chitinous intima pierces the j)rotoplasm of the cell, increasing in 

 diameter, and describes several curves, probably ending blindly. 

 Forel ascribes the peculiar smell of some ants (e. g. Tapinoma) to the 

 secretion of these anal glands : he has seen it ejected on an enemy. 



Parthenogenesis in Bees. — In continuation of the discussion on 

 this subject (see p. 88), M. M. Giard * considers that the true explanation 

 of the observation of M. Perez is to be found in a supplementary means 

 of nature to assm-e the reproduction of the immense posterity of the 

 social Hymenoptera. Besides the normal queens, which lay continually, 



* ' Comptes Reudus,' vol. Ixxxvii. (1878) p. 755. 



