INTRODUCTION. 



xvu 



have six palpi. Tlie inner lobe is variously provided on the inner 

 margin with eilias, spinous hairs, or even spines, and by a rare 

 exception, as in most Cicindelida?, the apex is terminated by a 

 movable hook. 



The maxillary palpi, which arise exterior to the lubes, are 

 usually. 4-jointed, rarely 3-jointed, and in Aleochara alone 5-jointed 

 Ijy the addition of a minute terminal piece ; they vary in form, 

 being filiform or dilated, and are occasionally of great size, as in 

 most Pselaphidoe; sometimes very long and slender, as in most 

 Hydrophilidaj; in the Rliynchophora they are very short and 

 rigid; the last joint is very variable in form; when suddenly nar- 

 rower and more slender than the preceding, the palpi are called 

 subulate. 



Mouth-parts or Trophi: 1. Head of Compsus with deciduous mandibular appen- 

 dages ; 2. The same of Tiigonosoiita ; 3. Head of Lixus with rostrum and scrobe ; 4. Bi- 

 lobed maxilla of Calosoma ; 5. (Jnilobcd maxilla of Epuraa ; 6. Serrate maxillary palpus 

 of Serropalpus, last joint cultriform; 7 Maxillary palpus of Xylita, last joint securi- 

 form ; 8. Subulate maxillary palpus of Bembidium ; 9. Bisetose labial palpus of I'tero- 

 stichus ; 10. Plurisetoso labial palpus of Harpalus ; 11. Mentum and labium of Morio, 

 with tooth and epilobes, ligula and paraglossa; free; 12. Same of Diplochila, with hypo- 

 f;lottis or basal membrane of ligula : 13. Mentum and labium of Calosoma within tin* 

 mouth, the paraglossse confluent behind the liirula ; 14. Mentum and ligula of Apho- 

 nus ; 15. Tip of rostrum and mandibles of Rhynchites ; IG. Maxilla and palpus of Eupa- 

 godcres ; 17. Maxillary palpus of Cedius ; 18. Same of Ceophyllus ; 19. Same of Tmesi- 

 phorus. 



Mentum and Lahium. — Beneath the maxilla', and between 

 them, funning the floor of the mouth, may be seen the mentum 

 and labium. 



