with particular regard to the Danish Fauna, 191 



generation alone, and not at all in the service of nutrition. 

 They monopolize almost the whole bulk of the muscles which 

 the head can accommodate. The other parts of the mouth — 

 labrum, maxillae, and labium — are often, as it were, merely 

 sketched in their development, or play the part only of pads 

 filling up the space round the bases of the mandibles. The 

 maxillae often remain undeveloped except the palpi, and all 

 parts and appendages of the labium coalesce. Besides, all these 

 animals are active by night, and the large night-eyes leave 

 hardly room enough on the small forehead for the antennae, 

 which, as we shall explain more fully hereafter, are endowed 

 with peculiar organs of sensation. This is the type represented 

 by the Prioni and those other forms which will be subsequently 

 pointed out as their nearest relatives. 



Whilst the two types hitherto described are so far connected 

 that the second may be described as a modification of the first, 

 the third type, that of the Lamice, occupies a more isolated 

 place, approaching more to the Chrysomelini. In this type we 

 find the maxillae and the labium again fully developed; but 

 their more powerful structure, shortness, and spinulous arma- 

 ture show that they are calculated for a more substantial 

 kind of food than pollen. The mandibles are compressed, 

 flat, entirely destitute of fold, fringe, membranaceous margin, 

 or molar tooth ; and although their points are well deve- 

 loped for their special use, viz. the perforation of timber, they 

 never assume the shape of pincers, &c., as met with in the 

 Prionini. The lingua is undivided, or only incompletely divided, 

 and the narrowness of the fulcrum linguae corresponds with the 

 limited strength demanded for the support of the lingua. The 

 labrum is visible ; but, as the whole region behind the mouth 

 (hypostoma) is abbreviated, the forehead becomes perpendicular, 

 as indeed befits animals living, in their larval state, in slender 

 pieces of timber, which the perfect insect has to perforate dia- 

 metrically. In spite of the length of the face, the space avail- 

 able for antennae and eyes is therefore but small, and a part of 

 the eyes is accordingly blinded. 



Having thus placed the organs of the mouth in the foremost 

 rank, I proceed to notice several other peculiarities of structure 

 which have not been taken into due consideration before, but 

 which I think of high systematic value. 



Although it is a well-known and often noticed fact that 

 Cerambyces are endowed with organs of sound, naturalists have 

 hitherto treated these organs with less attention than they de- 

 serve. The well-known creaking sound is produced by rubbing 

 the sharp, downward-bent posterior margin of the pronotum 

 against a circumscribed spot on the mesonotum, which spot 



