ANTS. 



veloped aiul comprise- a large cluster of cells in each side of the head 

 ju>t in front of the optic ganglia. Their ducts, grouped in bundles, 

 hut not uniting, open separately on a crihellum, or sieve-like plate on 

 the thin wall of a larger cavity, which narrows anteriorly and opens 

 as a small slit at the base and near the upper surface of the 

 mandible. The maxillary glands ( m.v ) consist of two groups of cells 

 near the median sagittal plane of the head, above the buccal tube and 

 near the infrabuccal pocket. Their separate ducts open on each side 

 on a cribellum in the lateral wall of the buccal tube. The labial, 

 usually called the salivary glands, are paired, like the preceding, but 

 are situated in the thorax. Their duct, however, is unpaired and opens 

 on the labium. These glands are derived from the spinning glands, or 

 sericteries of the larva. In Formica rufa, according to Meinert, each 

 of the lateral ducts, before uniting with its fellow to form the unpaired 

 terminal duct, becomes inflated and functions as a receptaculum for 

 the glandular secretion. 



The metasternal glands (Fig. 18), which \vere first seen by Meinert 



and Lubbock, have been 

 carefully investigated by 

 Janet. He regards them 

 as belonging to the epi- 

 notum and calls them 

 "glands de 1'anneau 

 mediaire," but Emery 

 asserts positively that 

 they belong to the meta- 

 sternal or ventral pieces 

 of the third thoracic in- 

 stead of to the epinotal, 

 or first abdominal seg- 

 m e n t . In M vnnica 

 rubra, according to Janet, 

 " the fine ducts of the 

 numerous gland cells 

 unite in a large bundle 

 and open separately on a depressed cribellum, situated on the ceiling of a 

 large chamber formed by an invagination of the chitinous exoskeleton. 

 From near the surface perforated by the orifices of the secretory ducts, 

 seven or eight little chitinous folds arise and extend laterally along the 

 walls of the chamber. These folds, which form small projecting ridges, 

 soon unite in two groups which border a small gutter on a slight 

 eminence. Towards the ventral region all traces of the ridges dis- 



- c 



f 



FIG. 18. Section of metasternal gland of La- 

 sius flavus. (Janet.) a. Orifice of episternal cham- 

 ber ; b, hairs guarding orifice ; c, cribellum ; d, gland- 

 cells ; c, ducts of same ; /, trichodes projecting into 

 episternal chamber : g. ganglion. 



