ANTS. 



and Emery ( i888f). who have found it to vary greatly and to afford 

 valuable characters for the delimitation of genera and even of sub- 

 families. The proventriculus of our common carpenter ants (Cain- 

 ponotns) may be described as a paradigm ( Fig. if), ./ \. it is a narrowed 

 or constricted portion of the alimentary tract and consists of several 

 successive sections. The most anterior of these is the calyx (c). As 

 the name implies, this is a cup-shaped section with chitinous walls dif- 

 ferentiated into eight bands, four greatly thickened, and very convex 

 towards the lumen, alternating with four thinner chitinous bands which 

 are more or less concave towards the lumen. The thickened bands 

 have been called the sepals. At the posterior narrow end of the calyx 



.-k 



FIG. 16. The gizzard, or proventriculus, of various ants. (Emery.) A, Canifo- 

 notits ligniperdus ; B, Lionietopinn microcephalum ; C, Atia sexdens ; D, Cryftoccrns 

 titrates; E, Technoniynnc.r stronins, seen from the anterior end; F, sagittal section 

 of same ; a, oesophagus ; b, crop : r, sepal ; d. membrane between sepals ; e, valve : 

 /, bulb of calyx (pumping stomach proper) : g, cavity of bulb; h, cylindrical portion; 

 i, knob-shaped valve ; k, stomach, or ventriculus. 



these can be applied so closely to one another as to shut off the lumen 

 and thus assume the function of a valve at this point. Posterior to 

 this valve, the walls of the organ again dilate suddenly to form a globose 

 section, the bulb (/(.which repeats the structure of the calyx with some 



