INTIIODUCTION. 



between the labial palj^i, the I'lgula or tongue (tig. 4, m), en- 

 sheathed at base by the parar/lossce (fig. 4, I, I). Both the ligula 

 and paraglossae are very variable in form. On each side of the 

 labium are the mcLvilhn (tig. 5), sheath-like organs with a basal 

 portion, the stipes (fig. 5, n\ and an apical lobe, the galea (fig. 5,p). 



Fiq.2 



ri4.4f. 



F,^.5. 



Fig. 2. — Common Honey-bee {Apis mellifera). Front view of head muck 

 enlarged, a, vertex; b, ocelli ; c, front ; d, d, compound eyes ; e, e, scape 

 of antenna;; /, /, flagellum of anteunje; g, clypeus ; h, labrum ; i, i, 

 mandibles ; k, k, labial palpi ; I, one of the paraglossffi of the tongue ; 

 m, ligula or tongue ; n, maxilla. 



Fig. 3. — Xylocopa, dissimi/is. Front view of head much enlarged, a, vertex; 

 f.', ocelli; c, front; d, d, compound eyes; e, e, scape of antenna , /'. /, 

 flagellum of antennic; //, clypeus ; h, hibrum ; i, i, mandibles. 



Fig. 4. — Xylocopa dUsimilis. Labium much enlarged, k, k, labial palpi ; 

 /, I. )iaraglo.'!sae ; m, ligula. 



Fig. .5. — Xi/locopa dissimilis. Maxilla much enlarged, w, stipes; <;, maxillary 

 palpus ; p, galea. 



Close to the junction of the stipes with the galea spiings the 

 max'illary paljyus (fig. 5, o). The form and structure of the mouth- 

 parts are of great value in the classification of the Hymenoptera. 



The thorax proper is composed of three segments — the pro-, 

 meso-, and metathorax. The jprothorax is I'emarkable for the 



