18 COLKOPTERA OV INDIANA. 



have but four. Sometimes the iiuml)ei' of joints varies in the sexes 

 of the same species. 



In form the tarsal joints may be slender and cylindrical, com- 

 pressed, flattened and dilated, globular, triangular or cordiform. 

 Frequently the next to last joint is notched or even bilobed. In 

 some genera the under side of one or more of the joints bear mem- 

 branous flaps called tarsal lohes. Usually, however, the under side 

 is clothed with spines, hairs, spongy pubescence or small scales. 

 Oftentimes the nature of this lower covering varies according to sex. 

 The front or middle tarsi, or both, are often dilated in the male, 

 and simple, or not dilated, in the female of the same species. 



The last joint of tlie tarsus bears two claws, often called ungues, 

 but in this paper termed tarsal chiirs. They also vary much in size 

 and shape and the character of their lower edge. They are usually 

 free and independently movable, l)ut are sometimes united at base 

 or even nearly to the tip, when they are said to l^e connate. Other 

 terms applied to them are (a") simple, when they have the ordinary 

 pointed form slightly but not suddenly broader at base; (&) diver- 

 gent, w^hen without being distant at base they diverge slightly; (c) 

 divaricate, when they arise from opposite sides of the joint and 

 form a right angle with it; (d) cleft, when each claw is deeply di- 

 vided into two acute parts which may or may not he of equal length ; 

 (e) hifid, when the tip only is divided; (f) appendiculatc, when 

 provided with a square dilatation at the base; (g) tootJied or ser- 

 rate, when they bear one or more acute teeth on the lower edge; 

 (/() pectinate, when the teeth are long, numerous and arranged like 

 those of a comb; (/) chelate, when the claws are capable of being 

 drawn back upon the last tarsal joint and thus enable the beetle to 

 grasp more firmly small twigs or leaves. Between the claws there 

 often occurs a small pad or flap wliicli is more or less retractile, 

 called the onychium. One of the claws is often much smaller than 

 the other and rarely one or even both of them are absent. 



The Abdomen. 



The third or hindmost portion of the body is called the ahdomen. 

 It consists of nine or ten rings or segments placed end to end, the 

 basal one being attached to the metathorax. Of these but five to 

 seven are usually visible, the others being retracted or coalescent at 

 base and tip. These rings are divided into two portions, the upper 

 or dorsal segments more or less covered l\v the elytra, and the lower 

 or ventral segments visil)le beneath. These dorsal and ventral seg- 

 ments are joined by memlirane along the sides above, the next to last 



