i892.] 



THE BRITISH NATURALIST. 



2 lO 



genus Corticnria fdenticulata, serrata, fulva, clongafn, gibbosa, &c.] ; of 

 Crioceris asparagi ; oi Prasocuvis aucta, margijiella, and hannoveranna ; of 

 both British species of Tenebrio, and of many of the weevil 

 group have the anterior tibiae bent or curved while in the females 

 they are straight. In BytJiinus curtisii, Brynxis sangiiinea , and TycJiius 

 meliloti, the anterior tibiae of the males have a more or less sharp 

 tooth in the middle. A curious exception to the general rule occurs in 

 the genus Rliizotrogiis, in the females of which the anterior tibia^ are 

 furnished with three teeth on the outer edge, while those of the male 

 are quite plain. The males of the genus Geotrupes have a distinct 

 ridge or keel on the anterior tibia which terminates in one or two 

 teeth at the extremity, and the free margin of this keel is either plain 

 as in stercorarius, toothed as in spiniger, or serrate as in mutator, 

 sylvati CHS and vernalis. In most insects the anterior tibia ends in one 

 or two spines or hooks ; in many " weevils " these are present only in 

 the male, and in the males of a few species of Aphodius ( quadrimactdatus , 

 merdnvijis, prodvormis, contaminatits, luridus and depvessiis) these are 

 stouter, curiously bent or twisted and cut off very bluntly at the 

 extremity, while in the female they are slender and sharp pointed. 

 Singularly enough, while the males of the genera Attelabus and 

 Apoderus have the anterior tibiae terminated by a single hook, the 

 females have tv^'o hooks at the apex of these limbs. The male of 

 Bnichiis loti has a bifid tubercle at the apex of the intermediate 

 femora ; its ally B. atomnrius has a small tooth before the apex of the 

 intermediate tibiae ; while the male Claviger foreolatus has both the 

 femora and tibiae of the middle legs toothed. The males of m^zra 

 spinipes, convexitisc.ida and alpina have a few small teeth on the inner 

 side of the middle tibiae, which are absent in the female ; while the 

 males of many of the same genus have these limbs curved, as is also 

 the case in the same sex of Choleva agilis, of Corticnria crennlatn, 

 denticulata, elongata, Siud fenestralis. Again, in almost one half of the 

 species of the genus Epurcea the middle tibiae of the male is wavy on 

 the inner side or strongly widened at the extremity, while E. pusilla 

 has all the tibiae curved in this sex. In the male Limnebms truncatellus 

 the middle tibiae are arched and the hinder ones very much widened 

 and flattened in their distal two-thirds. The males of the Rhyncho- 

 phorus genera, Amalus and Phytobius, have the intermediate tibiae 

 hooked at the apex. It is in the hinder legs that we find the greatest 

 variety of sexual modifications, and two genera, Anisotoma among the 

 Clavicornia, and Donacia among the Phytophaga, especially illustrate 

 the diversity of sexual armature. In Anisotoma cinnamornea, dubia, 

 ovalis, bruunea, calcarata, &c., the hind legs — especially the femora — 

 of the male are very much elongated; in A. calcarata the posterior 

 thighs of the male end, each, in a large triangular tooth; in the same 



