ANTENNAE OF INSECTS. 



565 



FIG. 285. 



cornes, from the great length of the antennae, which are at least 

 as long as the body, and often longer. Among the Lepidoptera, 

 again, the conformation of the 

 antennae frequently enables us 

 at once to distinguish the group 

 to which any specimen belongs. 

 As every treatise on Entomo- 

 logy contains figures and de- 

 scriptions of the principal types 

 of conformation of these organs, 

 there is no occasion here to dwell 

 upon them longer than to spe- 

 cify such as are most interesting 

 to the Microscopist; Coleoptera, 

 Brachinus, Calathus, Harpalus, 

 Dytiscus, Staphylinus, Philon- 

 thus, Elater, Lampyris, Silpha, 

 Hydrophilus, Aphodius, Melo- 

 lontha,Cetonia, Curculio; Orthop- 

 tera, Forficula (earwig), Blatta 

 (cockroach); Lepidoptera, Sphin- 

 ges (hawk-moths) and Nocturna 

 (moths) of various kinds, the 

 large "plumed" antennae of the 

 latter being peculiarly beautiful objects under a low magnifying 

 power; Diptera, Culicidae (gnats of various kinds), Tipulidae 

 (crane-flies and midges), Ta- 

 banus, Eristalis, and Mus- 

 cidae (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 dis- 

 tortion 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. 



386. The next point in the organization of Insects, to which 

 the attention of the Microscopist may be directed, is the struc- 

 ture of the Mouth. Here, again, we find almost infinite varieties 

 in the details of conformation ; but these may be for the most 

 part reduced to a small number of types or plans, which are 

 characteristic of the different orders of Insects. It is among the 

 Coleoptera, or beetles, that we find the several parts of which the 

 mouth is composed, in their most distinct form ; for although 



Antenna of Melolontha (Cockchafer). 



FIG. 286. 



Minute structure of Leaf-like expansions of 

 Antenna of Melolonljia : A, their internal layer ; 

 B, their superficial layer. 



