510 EXTERNAL ANATOMY OF INSECTS. 



higher animals, has made it up to them by the variety 

 and complex structure of their organs of vision, where 

 we have only two points of sight, giving them more than 

 as many myriads. 



5. Antennae. — But of all the organs of insects, none 

 appear to be of more importance to them than their An- 

 tennce, and none certainly are more wonderful and more 

 various in their structure, and probably uses. Upon 

 this last particular I shall enlarge hereafter. Their 

 structure, as far as it differs in the sexes, I fully dis- 

 cussed in a former letter a ; and the most remarkable 

 kinds of them will be included in a set of definitions 

 which I shall draw up for you before our correspondence 

 on this part of my subject closes : I shall therefore now 

 confine myself to the following particulars — namely, their 

 number, insertion, substance, situation, "proportion, general 

 form and structure, clothing, expansion, motions, and sta- 

 tion of repose.. 



As to their Number, in the majority of crust aceous ani- 

 mals the antennae amount to four, but no insect has more 

 than two. A genus recently established ( Otiocerus Kir- 

 by b ) seems to afford an exception to this rule, since the 

 species composing it at first sight appear to have four, 

 and in some instances even six antennae ; but as only two 

 of them terminate in a bristle, the other, though pro- 

 ceeding from the same bed of membrane, may perhaps 

 be regarded as merely appendages. Germar, who has de- 

 scribed a species of this genus c under the name of Co- 

 bax Wintheri, considers these appendages as analogous 



a See above, p. 318 — . b Linn. Trans, xin. 



L ' Mae. der Entomolos. iv. 5; 



