THE HEAD AND MOUTH ARMATURE. 



39 



ing organs in the larva, and contented himself by describing 

 the head in the following manner : ' The first and smallest 

 segment exhibits the mouth opening on its ventral surface and 

 two pairs of papillae on its dorsal surface ' [2, p. 105] ; and 

 although he subsequently describes the mouth organs at con- 

 siderable length, he does not again refer to the maxillae, except 

 to mention ' two thread-like thickenings in the recently-hatched 

 larva, which spring from the angle of the mouth and run 



Fig. 6. — The head of the Cossus caterpillar after Lyonet. a, antenna ; nid, 

 mandible ; mx, maxilla ; mx-, the second maxilla ; /, ligula. 



obliquely towards the back ' [p. 108] ; and adds, ' the two 

 chitinous ridges of the newly-hatched larva are replaced in the 

 adult by a fan-like group of similar ridges, which diverge from 

 the angle of the mouth and form a half circle at the side of the 

 mouth opening ' [p, log] . These are his only descriptions of 

 the stomal disc. He refers subsequently to the two pairs of 

 papillae as the antennae and maxillary palpi [p. 120]. 



A comparison of the maxillae with those of a lepidopterous 



