I METAMORPHOSES OF INSECTS 19 



of attached organs, the mouth organs, are situated at 

 its inferior surface, and at the lateral and anterior 

 surfaces it carries the rudiments of antennae,* or 

 feelers, and the eyes where they are present. In 

 the perfect insect, the number and position of these 

 parts are precisely similar. It is only in a manner 

 true to say that the head of an insect is composed 

 of one segment. For though at the birth of the 

 larva no satisfactory separation of this portion into 

 segments can be detected, it is a fact that it, like 

 the other regions, is made up of several rings. 

 The exact number which enter into its com- 

 position has not yet been made absolutely clear. 

 Probably the head appendages which form part 

 of the organs of manducation are the proper 

 articulated members of distinct rings, and are 

 analogous to those which constitute the locomo- 

 tive organs of the body. Since each pair of the 

 latter is attached to a particular segment, in the same 

 manner it may be presumed that the mouth-parts were 

 attached, indicating an early separation of the head* 

 into three segments. Probably there were four, 

 and perhaps five. In many larvae a projecting papilla, 

 the spinneret, is situated within the mouth. It opens 

 into the glands that secrete the silken material with 

 which the owner spins its cocoon, and performs 

 similar tasks. It is an organ its function being no 

 longer needed that dies ere the insect reaches its 

 perfect stage. While still in the glands, silk is a 

 thickish viscous * fluid. When about to make use of 

 it the larva places the spinneret in contact with some 

 object, and quickly withdraws it, at the same time 



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