cm 



ANTENNA OF INSECTS. 



mation of the Antennae frequently enables us at once to distinguish 

 the group to which any specimen belongs. As every treatise on 

 Entomology contains figures and descriptions of the principal types 

 of conformation of these organs, there is no occasion here to dwell 

 upon them longer than to specify such as are most interesting to 

 the Microscopist : — Coleoptera, Brachinus, Calathus, Harpalus, Dy- 

 tiscus, Staphylinus, Philonthus, Elater, Lampyris, Silpha, Hydro- 

 philus, Aphodius, Melolontha, Cetonia, Curculio ; — Orthoptera, 

 Forficula (Earwig), Blatta (Cockroach) ; — Lepidoptera, Sphinges 

 (Hawk-moths), and Nocturna (Moths) of various kinds, the large 

 1 plumed ' antennae of the latter being peculiarly beautiful objects 

 under a low magnifying power ; — Diptera, Culicidae (Grnats of 

 various kinds), Tipulidae (Crane-flies and Midges), Tabanus, Eris- 

 talis, and Museidae (Flies of various kinds). All the larger Antennae 

 should be put up in Balsam, after being soaked for some time in 

 Turpentine ; but the small feathery Antennae of Gnats and Midges 

 are so liable to distortion when thus mounted, that it is better to 

 set them up in fluid, the Head with its pair of antennae being thus 

 preserved together when not too large. — A curious set of organs 

 has been recently discovered in the Antennae of many Insects, 

 which have been supposed to constitute collectively an apparatus 

 for Hearing. Each consists of a cavity hollowed out in the Horny 

 Integument, sometimes nearly spherical, sometimes flask-shaped, 

 and sometimes prolonged into numerous extensions formed by 



Fig. 342. 



Minute structure of Leaf -like expansions of Antenna of Melolontha , 

 a, their internal layer ; b, their superficial layer. 



the folding of its lining membrane ; the mouth of the cavity 

 seems to be normally closed-in by a continuation of this mem- 

 brane, though its presence cannot always be satisfactorily 

 determined ; whilst to its deepest part a nerve-fibre may be 

 traced. The expanded lamellae of the Antennae of Melolontha 

 present a great display of these cavities, which are indicated in 



