EXTERNAL ANATOMY OF INSECTS. 687 



they are as thick or thicker, or more dilated, as in most 

 of the tetramerous beetles, which being climbers require 

 a dilated tarsus. Again, comparing the three pairs of 

 this joint with each other, the most general rule is, that 

 the anterior should be the shortest, and the posterior the 

 longest : but in some, as the Capricorn beetles, &c, they 

 are nearly equal in length; in others, as Lytta marginata, 

 the anterior pair, and in Rhipiphorus the intermediate, 

 are the longest ; in Trichius Delta these last are the 

 shortest. With respect to thickness, the anterior tarsi, 

 except in many males 3 , are not very strikingly different 

 from the rest. 



With regard to the proportion of the joints of the 

 tarsus to each other, — according to the most general law, 

 the first is the longest, the last next in length, then the 

 second and third, and the fourth is the shortest. In Gony- 

 leptes K. and other Phalangitis the first is almost thrice 

 the length of all the rest taken together ; but there are 

 numerous exceptions to the rule. In the female Carabi 

 the first joint is not longer than the last, and in the males 

 not so long ; and in Hydrophilus, &c, it is the shortest of 

 all. Again, the second joint is longer than the three fol- 

 lowing ones in Dasytes ater b ; and than the last in Cicindela 

 sylvatica : the third joint is shorter than the fourth mLam- 

 pyris ignita : it is longer than the first in Donacia, many 

 Melolonthida, &c. Once more, the fourth joint, usually 

 the shortest of all, is longer than the second and third 

 in Anthia, &c. Lastly, the claw-joint, usually the second 

 in length, in the Eproboscidea Latr. (Hippobosca L.) is 

 very long and large, while the four first joints are so 



a See above, p. 335—. b Plate XXVII. Fig. 25. 



