122 THE INTEGUMENTAL SKELETON OF THE IMAGO. 



The Antennae hang vertically in front of the mesofacial plates; 

 they are usually said to consist of throe joints and a bristle! 

 They are really six-jointed, as Desvoidy pointed out, with a 

 greatly enlarged third joint, the three terminal joints being 

 reduced to the form of a three-jointed bristle. The large third 

 joint is cylindroid, and slightly prismatic. It contains a 

 complex sensory organ, which is undoubtedly olfactory (see 

 ' Sensory Organs '). 



The Posterior Surface of the head capsule consists of the 



lo 24 _/ 1 he I'ace of the Jilow-Hy : ep, epislome ; / facial edge of paracephalon ; 

 /«, unula ; mf mesofacial plate ; r, rostrum ; (r, torulus. 3, the Metacephalon 

 of the same : h, basal scleritc orgula ; bs, basal suture ; cc, cotyloi.l cavity ■ ,ir 

 dorsal ring ; ep 0, epioccipital sclerites ; j^ andy-', first an,l secon<l jumdares'- iu 

 jugum ; /J, paracephalic suture. '^ 



posterior part of the paracephala (Figs. 23, ^, /, and 24). the 

 occipitals of Mcnzbier, the epicephalon (w), the pars basilaris 

 (6), and the metacephalic ring surrounding the occipital fora- 

 men. 



The occipital, or metacephalic, ring (Fig. 24) consists of two 

 lateral parts, and of a dorsal and a ventral arch. 



The lateral parts are concave externally and convex inter- 

 nally ; they each give off a process to form the jugum, and are 



