8 INSECTS. 



sidered as an evolution or successive display of 

 parts before concealed. Thus Swammerdam de- 

 clares that he could demonstrate all the parts of 

 the future Butterfly even in the body of the cater- 

 pillar itself. The truth of this experiment of 

 Swammerdam has been sometimes vehemently 

 doubted, and even denied by some; especially as 

 it is difficult, at first, to discover these parts even 

 in the chrysalis or pupa, which is a step nearer to 

 the complete Insect. But in reality, there seems 

 to be but small reason for questioning the truth 

 of Swammerdam's observation; and it may be 

 readily conceived that, by a very accurate and 

 delicate investigation, the rudiments of the future 

 fly may be distinguished in the Caterpillar, if 

 observed a few hours before its transformation 

 into a chrysalis. 



Insects possess some particular parts which are 

 not to be found in any of the larger animals. 

 Among these are the Antennae before mentioned, 

 which are generally termed the horns. They are 

 those processes or jointed bodies situated on each 

 side the head. The use of these parts is not 

 entirely understood*. It has by some been ima- 

 gined that they are the instruments of hearing. 

 They differ extremely in the different tribes of 

 Insects, and are found to constitute one of the 

 most convenient parts to fix upon in the distribu- 

 tion of Insects into genera and species. It is 



* See a highly learned and ingenious dissertation entitled, 

 <f De Sensibus externis Animalium Exanguium" by Mr. M. C. 

 Gottlieb Lehman, published at Gottingen in the year 1798. 



