54 



THE REPORT OF THE 



No. 36 



Moulting. When about to moult the nymph attaches its claws to the 

 surface and also inserts its mouthparts into the leaf tissue. The old skin splits 

 along the middle of the front, vertex and prothorax, and the nymph with a 

 slight wriggling motion gradually works its way out head foremost. The 

 whole process takes between five and fifteen minutes, and the nymph shortly 

 after moulting resumes feeding. 



Last moult of grape leaf hopper nymph. 



In the final moult the wings expand to full size as the body emerges from 

 the old skin. The hopper then moves away a short distance and rests until 

 the thin, transparent wings dry. The entire process takes about thirty minutes. 

 The colour markings may not develop for several hours. 



The exuviae of the first four instars are lightly attached to the leaf and are 

 soon blown away. The last moulted skin remains upon the leaf indefinitely. 



Length of Nymphal Life. The duration of each instar and the total 

 length of nymphal life of first and second brood nymphs reared in the insectary 

 are shown in the following table: 



First Brood 



Minimum 



Maximum 



Average 



First Instar 



4 days 

 4 days 

 4 days 

 3 days 

 3 days 



7 days 



6 days 

 5 days 

 5 days 



7 days 



5 . 7 days 



Second Instar 



5 . 3 days 



Third Instar 



4 . 2 days 



Fourth Instar 



4 days 



Fifth Instar 



5 days 







Total Nymphal Life. . , 



22 days 



26 days 



24 days 







Second Brood 



Minimum 



Maximum 



Average 



First Instar 



4 days 

 4 days 

 4 days 

 4 days 

 4 days 



14 Individuals 



5 days 



6 days 

 6 days 

 5 days 

 5 days 



4. 2 days 



Second Instar 



4. 5 days 



Third Instar 



4 . 5 days 



Fourth Instar 



4 . 5 days 



Fifth Instar 



4.5 days 







Total Nymphal Life 



21 days 



25 days 



24 days 







