OF THE MOUTH. 103 



obtuse blade or lacinia obtusa, is when it has no charac- 

 ter conspicuous or active, but terminates the feeler- 

 jaw in a rounded and apparently undeveloped form. A 

 falcate blade or lacinia falcata, is when its point is acute 

 and bent over towards the opposite blade : this kind of 

 blade has its interior edge hirsute, dentate, or simple; 

 its point bifid or simple. An articulated blade or lacinia 

 articulata, is when it unites with the disk of the feeler-jaw 

 by means of a distinct and free joint instead of a sutural 

 fixed line : it has this form in the tiger-beetles. The hel- 

 met m galea, o in the figure at p. 159, is situated on the back 

 of the feeler-jaw, behind the blade and before the feeler ; 

 its variations are very numerous, and, consequently, very 

 useful in assigning characters to insects. A palpiform 

 helmet or galea palpiformis, 6, page 159, is when it is 

 perfectly distinct from the blade, and composed of one, 

 two, three, or four cylindrical joints, like those of the 

 feelers or antenna : it has this form in carnivorous beetles. 

 An obtuse helmet or galea obtusa, is when it appears simply 

 as a shapeless mass ; it assumes this form frequently when 

 the lacinia is also obtuse, and much resembles it in ap- 

 pearance. An obsolete helmet or galea obsoleta, is when 

 it is closely united to the blade : sometimes a mere sutural 

 line, and occasionally not even that, denotes any separation 

 between them. The maxillary feeler or maxipalpus, 6 in 

 all the figures, rises from the feeler-bearer immediately 

 behind the helmet ; its principal variations are in the num- 

 ber, form and proportion of its joints : the descriptions of 

 these are very simple, and easily understood, without the 

 employment of any set terms. The mandibles or mandi- 

 bulce, i in the figure at p. 159 ? are situated immediately below 

 the upper lip, and immediately above the feeler-jaws, one 

 on each side of the mouth, meeting and sometimes crossing 

 in front : when possessed of motion, they move horizon- 



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