258 



THE BRITISH NATURALIST. [Nove MBER 



the antennas of the female are one fourth longer than those of the male 

 — a solitary exception to the general rule. In a few instances the 

 number of joints varies in the two sexes, thus : the males of Prionus, 

 Molorchus, and Nacerdes have the antennae 12 -jointed, while those of 

 the females have only the usual number 1 1 ; and in Holoparamecus 

 depressus the female has 10 joints to the antennae, while the male has 

 only 9. Pria dulcamara has the club of the male composed of 4 joints, 

 while that of the female has only 3— a fact which caused Stephens to 

 place the sexes in seperate genera. In the following species, we also 

 find the club of the antennae longest in the male : Serica brunnea, 

 Rhizotrogus, Throscus dermestoides, Anthrenus claviger, Megatoma 

 undata, &c. ; while the male of Attagenus pellio has the last joint of the 

 club as long as the whole of the other joints put together. The male of 

 Anthribus albinus bears at the end of each joint a tuft of white scales. 



In Diptera the males of Tipula flavolineata and longicornis, and of 

 Bolitophila fusca have much longer antennae than the females : but in 

 Maceocera both sexes have long antennae. The male of Rhapium 

 longicorne, also, has much longer antennae than the female. 



V. — Disparity of Palpi. 



The males of Hyleccetus dermestoides and Lymexylon navaie, two of 

 the Coleoptera, may be distinguished from the females by the large 

 size of the palpi. In Hymenoptera, the maxillary palpi of the males of 

 Mesopolobus, a sub-genus of Pteromalus, are furrate, the third joint 

 being externally prolonged. 



VI. — Disparity of Eyes. 



In the Diptera, the sexes may be distinguished from each other by 

 the position of the eyes, the males having them close together, the 

 females far- apart. This is especially the case in the Tabanidae, 

 Stratiomyidae, Syrphidae, and Muscidae. 



In Coleoptera, the eyes of a few species are more strongly developed 

 in the males than in the females. Examples are Lampyris noctiluca, 

 Ptinus lichenum and fur, Dryophilus pusillus, Luperus flavipes, 

 Lagria hirta, and Euglenus oculatus — where the eyes of the ; male are 

 nearly in contact. 



VII. — Disparity in Legs. 



In Lepidoptera, the only species I know of which can be separated, 

 the one sex from the other, by the legs, are those of the genus Herminia, 

 called, fan-foots ; the front legs of the male bearing a large tuft of hair. 



In Hymenoptera the males of Anthophora retusa and pilipes have a 

 most peculiar pair of middle legs, with long hairs projecting from them. 

 On the other hand, the female of Dasypoda hirtipes has a most pecu- 

 liar pair of hind legs, being covered with dense fulvous hair. In the 



