280 CLASS VIII. 



the eyes are large air-sacs or wide air-tubes, from which fine 

 branches arise, which in part run to the pigment and connect its 

 granules, in part pass into blind cylindrical tubes situated between 

 the nerve-threads of the vitreous cones 1 . 



DE LA HIRE, who first discovered the simple eyes of Insects, 

 thought he might conclude from their presence, that the larger 

 (compound) eyes were not organs of vision. That they also serve 

 for vision the experiments of SWAMMERDAM, who smeared them in 

 flies with black varnish, have proved. REAUMUR also did the 

 same with bees. It is more difficult to determine exactly in what 

 respects the office of the compound and simple eyes differs, although 

 the last probably serve principally for seeing near objects. The 

 bees, in which REAUMUR had smeared these eyes with a dark 

 varnish, whilst their compound eyes remained uncovered, could not 

 find their hives 2 ; moreover all flying Insects are invariably pro- 

 vided with compound eyes. There are Insects which have simple 

 eyes alone, as the Myriapoda and Parasitica (also the larvae of the 

 Lepidoptera] ; few Insects are entirely without eyes, like a parasitic 

 Insect of bees (Braula NiTZSCH 3 ), and a new genus of the Carabica 

 Anophihalmus of SCHMIDT 4 , and different Myriapoda. In the 

 diurnal butterflies and most Coleoptera, there are two compound 

 eyes alone, without simple eyes ; simple eyes are also wanting in 

 certain Diptera, in Forficula, Blatta and other Orthoptera, in many 

 Hemiptera / where they occur in company with compound eyes, 

 usually three are present, sometimes, as in Castnia, Sesia, Noctua, 

 Gryllotalpa, two 5 . 



1 See on the compound eyes of insects amongst others HOOKE, Micrographies 

 Londini, 1667, Tab. 24, SWAMMERDAM, Bibl. nat. pp. 487 498, Tab. xx., J. MUELLEB, 

 Zur vergl. Physiol. des Gesichtsinnes, Leipzig, 1826, 8vo. s. 307 390 ; by the same, 

 Fortgesetzte anatomische UntersucJiungen ueber den Ban der Augen lei den Insecten u& 

 Crustaccen, in MECKEL'S Arckiv, 1829, s. 38 64, and Ueber die Augen des MaiMfers, 

 ibid. B. 177 181 ; F. WILL, Beitrdge zur Anat. der zusammengesetzten Augen, Leipzig, 

 1840, 4 to; A. BRANTS on the air-tubes in the compound eyes of the Articulata, Tijd- 

 schrif. voor nat. Gesch. en Physiol. xn. 1845. 



2 Mem. p. servir a I'Hist. des Ins. v. pp. 287289. 



3 GERMAR, Magazin der Entomol. HI. 1818, s. 314. 



4 See JAC. STURM, Deutschland's Insecten xv. 1824, pp. 129 137, Taf. 303. Also 

 a genus of the Xylophagi, Anommatus terricola, ROBERT, A cad. roy. de Bruxelles, 1836. 



5 KLUG, Ueber das Verhallen der einfache Stirn und Sclieildaugen bei den Insecten 

 rn.it zusammenges Augen. Physikal-Abhandlungen der Konigl. Akad. der Wissensch. zu 

 Berlin, aus den Jahre 1831, s. 301 312. 



