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 diflicult, 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 Antemm 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 difler 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, 
Dc Sensibus externis Animaliuni Exangidum” by Mr. M. C. 
Gottlieb Lehman, published at Gottingen in the year 1798. 
