6 



CURCULIOMl)^. 



adopted has been to take Lacordaire's arrangement as a working 

 basis, making only such akei'ations as are necessary for the 

 inclusion of the numerous Indian species which wer9. unknown 

 to him. 



Structure of the Imago. 



Rostrum. — The most striking characteristic of the CuKCU- 

 LiOiS'iDyE is the prolongation of the head in front of the eyes, 

 forming a rostrum or bealv (fig. 2) which bears the antennse, the 

 mouth being situated at its extreme apex. This structure varies 

 immensely in its shape and development ; at one end of the 

 series it is extremely short, and almost as broad and deep as the 

 head in certain terrestrial Australian species (Amycterus) and 

 in a few Scolytid-like forms among the CossoNiN.ii, while in 

 Balaninus it is very slender and may be even longer than the 

 whole body ; and every intergrade between these extremes may 

 be found. Along each side of the rostrum tliere is always a 

 well-marked hollow or furrow, the scrobe, in which the antenna 

 is placed, the furrow being used for tlie reception of the elongate 

 first joint, or scape, when in a position of rest. The shape and 

 position of the scrobe afford useful taxonomic characters (fig. ] ). 



ma. Ttux. 





d. 



Fig. 3. — Mouth-parts of : a, E2nsomvs suhnitejis, Mshl. ; b, Dicranotropis 

 aschabadensis, Fst. ; c. Ajjoderus cygoieus. F. ; d, Alcides pectoralis, Eoh. ; 

 f, Sipalus hi/'pocrita, Boh.; ma, mandible; mc, lueutuni ; ^:)ff, maxillary 

 palpus ; ^JfZ, peduncle of submentum. 



Mouth- parts (figs. 2-5). — The mouth-parts are contained in the 

 terminal aperture, or buccal cavity, and in the species with a 

 slender rostrum thej^ are naturally much r(?duced in size. The 

 most noticeable feature is the great reduction of the palpi, which 

 are invariably very short and rigid (except in the Eiii>'OMACERTN^Ti:). 

 and often entirely concealed. In various groups the mentum 

 exhibits striking differences in its relation to the otlier parts of 

 the mouth (fig. 3), and this was utilised by Lacordaire in his 

 primary division of the family into Curculionid.tj Adelogivathi 

 and CuECULioNiD^ Phaneeognaxhi. In the Adelognathi 

 (figs. 3, «, and 4, rt, c) the large, obtuse and pincer-like mandibles 

 occupy the greater part of the buccal cavity and the small space 

 left behind them is completely or almost completely filled by the 

 mentum. In the completely adelognathous genera the maxillae 



