with particular regard to the Danish Fauna. 195 



PsALipoGNATHUS. — A Small spot at the apex of the third and fourth 

 joints; on the following, two long deep furrows separated by a 

 ridge. 



Anacolus. — Two long poriferous canals on each joint. 



Anacanthus. — A rather short spot on the third joint; a longer 

 one on the fourth ; on the following, two long furrows separated 

 by a ridge. 



Acanthophorus. — Third, fourth, and fifth joints with two spots 

 separated by a ridge, which on the following extend to the whole 

 length of the joints, and on the very last combine to form a con- 

 tinuous poriferous surface. 



pRiONONEMA. — Two spots ou cach joint, extending their whole 

 length, and deeper in the male ; on the last joint a continuous 

 poriferous surface. 



Cyrtognathus. — Third to fifth joints flat underneath, quite co- 

 vered with pores ; on the fourth and fifth joints also a small and 

 narrow spot on the anterior surface ; on the following a continuous 

 poriferous surface. 



Prionus, Tragosoma. — The whole of the antennae, excepting 

 only the base of the third joint, covered with innumerable small 

 oblong spots with raised intervals, having the effect of a reticula- 

 tion. 



Macrodontia. — The spots innumerable, small, scattered over the 

 whole surface, and so close to each other that the intervals form 

 a net. 



Erioderus. — The under surface of the third joint and all the fol- 

 lowing joints entirely and closely covered with minute pores. 



There is a great variation in the size, depth, shape, and rela- 

 tive position of the pores themselves. Upon the whole, they are 

 somewhat more numerous in the males than in the females. 

 The object of the leaf- or tooth-shaped expansion of the joints 

 so often met with is evidently to gain increased room for pores. 



In all other Cerambyces the antennse are covered with hair, 

 as in Insects generally. The hairs of the pores, being also 

 more or less developed, are generally lost in the multitude of 

 ordinary hairs, so that they can be distinguished only by means 

 of the microscope. In some cases, however, they are grouped 

 together in certain places in such a manner that they are per- 

 ceptible by means of a moderate lens, and may be used for the 

 pm'poses of classification. In those genera which form my 

 group Asemini they are collected in spots, in the manner de- 

 scribed below. In many Cerambycini they are set in long fur- 

 rows along the under surface of the joint, as, for instance, in 

 Callichroma moschata, whose black antennse, however, on ac- 

 count of their colour, are less suitable for microscopic inspec- 

 tion than the light-coloured antennse of several exotic species, 

 for instance of Trachyderes, Poriferous grooves are sometimes 



13* 



