20 ANTS. 



1 lymenoptera, such as the- wasps, covers the mentum and paraglossae. 

 Its upper portion is somewhat lobed and hears two rows of backwardly 

 directed bristles, which form a V and seem to be used for holding the 

 food fast in the month. The upper lip, or labrnm, forms the roof of 

 the mouth. It is poorly developed and consists of a bilobed plate 

 hidden beneath the anterior border of the clypeus (Fig. 4, #/>). 



The an ten me are far and away the most important sense organs of. 

 the ant. They are inserted in sockets on each side of the frontal 

 carinae, and consist of a series of joints of variable number and length. 

 The lowest number, four, is found in the genus Epitritns (Fig. 75) ; the 

 greatest, thirteen, in the males of many of our common ants. Usually 

 the males have one more joint than the females and workers. The 

 first joint, known as the scape, is always considerably elongated, except in 

 the males of some species. The remainder of the antenna, the funiculus, 

 consists of very much shorter joints, the articulations between which 

 are less movable than that between the scape and funiculus. This 

 latter articulation is of such a nature that the funiculus can be folded 

 up against the scape producing the peculiar Formicid elbow in the 

 antenna, and both this and the socket articulation at the insertion of 

 the scape permit extraordinary freedom in the movements of the 

 appendage. The funiculus may be of nearly uniform diameter through- 

 out, with very similar joints, or from one to four of the terminal joints 

 may be thickened and elongated and thus constitute a club. 



Ants have two kinds of eyes : the compound, lateral eyes, two in 

 number and placed on the sides of the head (Fig. 4, /), and the simple, 

 median eyes, ocelli, or stemmata, of which there are three on the vertex 

 ( Fig. 4, ;;/, n }. Both kinds are best developed in the males, less in the 

 females and least in the workers, which often lack the stemmata 

 altogether. In addition to these great differences, which are constant 

 in the three phases of nearly all species, there are considerable differ- 

 ences in the development of the eyes in the different genera. A more 

 detailed account of these organs and the antennal sense organs is given 

 in Chapter IV. 



The Thorax. Owing to the fusion of the first abdominal segment 

 of the embryo and larva with the hindermost portion of the thorax 

 during pupation, the thorax of the adult ant may be said to consist of 

 four segments, a pro-, meso- and meta-thoracic and a mediary segment, 

 or epinotum. In our description we may follow Emery (19000?) who 

 has carefully studied the external morphology and reviewed the nomen- 

 clature of these four segments in the male, female and worker. The 

 primitive condition of the thoracic region may be readily traced through 

 the ergatoid females and workers of these forms to the much reduced 



