THE APPENDAGES OF THE HEAD. 



27 



crgans ; while the same insect, when evidently atiected by 

 sounds, keeps them motionless in one direction, as if in the act 

 of listening." (Newport.) 



After cutting off one or both antenna* of the June beetle, 

 Lachnosterna, the insect loses its power of directing its flight 

 or steps, wheeling about in a senseless manner. Dr. Clemens 

 observed that the Cecropia moth was similarly urtected after 

 losing its antennffi. 



The MitiidihJes (Fig. 37) are inserted on each side of the 

 mouth-opening. They usually consist of but a single joint, 



H 



Fig. 37. 



representing probably the basal part of the ideal limb. This 

 part, however, is often subdivided bj^ two longitudinal fuiTows 

 into three parts, each ending in a "tooth" of unequal size for 

 tearing and cutting the food. This tripartite for;n of the man- 

 dibles, to which attention has been called by Mr. Scudder, is 

 more fully carried out in the maxilla, where each portion is 

 highly specialized. The mandililes vary greatly in form and 

 size. The tAvo cutting edges are usually opposed to each other, 

 or frequenth' overlap in the carnivorous forms. Their base is 

 often concealed by the clypeus 

 and labrum. Their motion is 

 transverse, being the reverse of 

 the motion of the jaws of Ver- 

 tebrates. 



The Maxilkti (Figs. 38 7>, 39) are 

 much more complicated organs than the mandibles. 



Fig. 37. Diffevcnt forms of mandible.*. A, mantWWe oi Cicindelapttrpurea; B. 

 Phylloptera, n green grassliojiijer; C, LibelUihi iriiiiitnilata; T>, yespa muculata, or 

 j)aper-making Wasp: E, "rostrum" or jointed sucker of the Bed-l)Ug, Cimex lectu- 

 liiriuK, consisting of mandibles, ma.xilhi', and labium; F, proboscis, or sucker, of a 

 Mosquito, Culex, in which the mandibles are long and bristle-like. — [•Yom Sanborv. 

 (i, mandible of Amphizoa ; H, mandible of Acrutus,A genus of Cockchafers. — From 

 Horn. 



Fig. 38. «, montuni and laliial palpi; /), one maxilla, with its palpus, of Arnt- 

 ius. — From Horn. 



Fig. 30. Maxilla of Amphisoa. with the two lobes (stipes and lacinia), and the 

 palpifer bearing the four-jointed palpus.— /■Vo»? Horn. 



Fig. 39. 



Thev are 



