FIELD NOTES ON BUTTERFLIES 



Eggs of the large or the small white butterflies, for 

 example, are very insignificant objects that may often 

 be seen in dozens when looked for. They will be found 

 standing upright on either surface of a leaf of the fami- 

 liar cabbage growing in the garden. Place one of these 

 eggs, which are more or less skittle-shaped, under the 

 microscope, and it will be seen to have several ribs 

 extending from the blunt apex to the base, and a num- 

 ber of finer lines around its circumference. Probably 

 when first noticed the eggs may be greenish or yellow- 

 ish-green, but if kept under observation for a few 

 days they will be found to turn greyish. The last 

 change in colour indicates that the caterpillars will 

 soon emerge from the eggshell. To enable it to make 

 its debut the young caterpillar bites through the 

 shoulder of the egg, and before it emerges therefrom it 

 has eaten a large portion of the shell. It is of course 

 exceedingly small at first, and very unlike what it will 

 become when full-grown. Its existence as a cater- 

 pillar is of comparative short duration ; but this stage 

 is nevertheless a most important one in a butterfly's 

 career, and full of stirring episodes. Not only has it 

 to pass through the ordeal of changing its skin on several 

 occasions, but enemies, especially those in the shape 

 of parasitical flies, are ever on the watch to destroy it. 

 The flies deposit their eggs on the back of the cater- 

 pillar, and the tiny grubs that hatch from these enter 



