1H8 THE CANADIAN ENTOMOLOGIST. 



which was kept under a bell jar, while the other was enclosed in a breed- 

 ing cage. At the end of the second instar a marked difference was 

 observed in the rapidity of development of the two lots. All the larvae 

 confined beneath the bell jar passed through the second ecdysis before 

 one of those in the breeding cage had reached that point. The only 

 observable difference in conditions was a greater abundance of moisture 

 beneath the bell jar, which would naturally improve the food by keeping 

 it fresh and tender. The second instar thus ranged from 5 to 7 days. 



Third Instar. — The second ecdysis produced a marked change in 

 colour in larvae : the light green became dark green, and the light yellow- 

 stripes were much more conspicuous. 



Two Days After Moult. — Average length at rest about 12 mm.; 

 form as before. General colour varied from dark brownish-green to as 

 light green as in previous instar ; in light-coloured specimens, however, 

 the broad dorsal stripe is much darker than the other stripes, and also 

 darker than it was in the second instar. 



Clypeus and labrum usually lighter coloured than rest of head ; 

 head somewhat mottled with green ; antenna? at their bases as light 

 coloured as labrum ; mandibles yellow, tipped with black. 



Spines and stripes present as in previous instars ; substigmatal white 

 stripe has become broader, and tubercles IV. and V. stand therein ; 

 spiracles conspicuous, dark brown. 



The third moult took place in about six days after the second, and 

 produced a great change in the appearance of the larvae. It required 

 less than forty- five minutes to get rid of the old skin after it began to 

 rupture around the throat. 



Fourth Instar. — Two Days After the Moult. — Length at rest about 

 18 mm.; form cylindrical, segmentation distinct. Head equal in size to 

 any following segment, rounded, mottled brown and light green in colour, 

 darkest on sides of lobes ; clypeus triangular, extending nearly to head, 

 its vertex connected by a light-coloured depression, with vertex of a white 

 triangular area lying on top of head between the lobes ; antennae and 

 labrum light coloiued. The wide variation between light and dark speci- 

 mens noticed in last instar has disappeared, so that the coloration has 

 become quite uniform in different individuals ; body marked with dark 

 brown and white stripes ; dorsal stripe broad and dull blackish in 

 colour ; subdorsal white stripe clearly defined, quite narrow ; lateral 

 stripe, which was dark in previous instars, has become changed almost 



