LIFE HISTORY OF THE MOTH 1 



1. The life history of the Moths and of other Insects with complete 

 metamorphosis consists of four stages, namely, egg, larva, pupa, and 



ADULT. 



(a) Egg. The eggs of a Moth are generally laid on, and attached to, 

 leaves which later serve as food for the larvae. Examine, with the dis- 

 secting microscope, a preparation of a leaf with the attached eggs and 

 make a drawing. 



(b) Larva. Examine the segmented, worm-like, larval stage of the 

 moth (caterpillar) and make a drawing to show the following struc- 

 tures : (i) the head, which appears as one segment and bears on its ante- 

 rior surface tiny, simple eyes (ocelli) and, laterally on each side of the 

 mouth, a pair of jaws (mandirles) ; (ii) the thorax, consisting of three 

 segments, each of which bears a pair of small jointed appendages with 

 sharp hooks, and (Hi) the ardomen, consisting of the posterior nine seg- 

 ments, of which five bear unjointed appendages, known as prolegs. 

 Note the openings (spiracles) of the tracheal tubes on each side of certain 

 segments. Draw the animal from the left side to show the structures 

 observed. 



(c) Pupa. Examine the silky cocoon which the animal spins and in 

 which it encloses itself at the end of the larval period. Carefully open 

 the cocoon by making a longitudinal cut through the wall with the tips of 

 the scissors. Remove the living pupa and examine under the dissecting 

 microscope. Identify the head, thorax, ardomen, antenna cases, 

 wing cases, and leg cases. Make drawings of (i) the cocoon, and 

 (ii) the pupa from the ventral surface. 



(d) Adult. Examine an adult Moth. Identify (i) the head, with 

 eyes and antennae ; (ii) the thorax, with fore and hind wings, and 

 three pairs of legs; and (Hi) the segmented ardomen. Compare the 

 various structures with those seen in the Bee. Make a drawing of the 

 dorsal surface, showing all structures possible. 



i B. pp. 130-133. 



303 



