FEET OF THE DYTICUS. 57 



The first pair of legs, however, are the most interesting. 

 We have already seen tliat, in very many Beetles, the tarsi of 

 the front pair of legs are dilated in the male, but there are 

 none which even approach those of the Dyticus in complexity 

 of structure. The geodephagous males have the under surfoce 

 of tlipse dilated joints merely furnished with a pad, but the 

 yDyticus has a most wonderful iirray of suckers, exactly analo- 

 gous in principle to those which stud the arms of the cuttle- 

 fish. One of these legs is shown on Woodcut No. VI. Fig. c. 

 The three basal joints of the tarsus are enormously swollen, so 

 that they assume a plate-like shape. Their upper surface is 

 smooth enough, but the imder surface is covered with suckers, 

 one of them very large, and the second about half its size, and 

 a multitude of smaller suckers. The larger suckers are placed 

 directly upon the joint, and the others are at the eud of 

 slender footstalks, looking something like the ' patera ' cham- 

 pagne glasses with the stems much attenuated. 



In order to see this beautiful structure properly, several 

 specimens ought to be used. One can be simply cleaned, and 

 viewed as an opaque object, while another is cut so as to give 

 a section of the joints, and to show the manner in which the 

 suckers spring from them. Three more specimens should also 

 be prepared, but mounted as transparent objects in Canada 

 balsam. This will be found rather a difficult process, but one 

 which will very well repay all the trouble. The difficvdty is 

 to get rid of the air which remains in the suckers, and which 

 makes the mouth of each sucker look like a black shining ball. 

 A structvu'e, similar in principle, though varying in detail, is 

 found throughout this group of Beetles. 



The female is, as has been stated, very different from the 

 male in appearance. She does not possess the wide tarsi which 

 are so conspicuous in her mate. The elytra are very different 

 from those of the male, and, instead of being smooth and 

 polished, are deeply grooved nearly as far as the middle. 



The voracity of this Beetle is really astonishing. It will eat 

 almost any kind of insect, or any kind of meat, raw or cooked, 

 preferring the former. Sometimes it is placed in fresh- water 

 aquaria by those who are not acquainted Avith its powers, 

 and the result is always disastrous. Not only will it attack 

 every living creature in the aquarium, but during the night; it 



