HOW TO OBSEKVE INSECTS. 3 1 



Figure 33. 



Checkered white, male. Checkered whita, female. r 



Closely observed they will be seen to alight occasionally on a 

 leaf, usually on the under side,, and then to fly away to i another 

 plant. If the exact place on the leaf where one alights be care- 

 fully noted and then examined after the butterfly has departed, 

 there will generally be found a single egg that has been attached 

 there by the insect. This is of a light yellow color, and on examir 

 nation with a leiise is seen to be most beautifully and regularly 

 marked with longitudinal ribs. If possible, the pupils should 

 watch the butterflies laying their eggs in the field. In any case', 

 there should be brought into the school-room, in a pot or box, one 

 or more living cabbage plants on which eggs have been deposited. 



In a few days there hatches from the egg a tiny, green, worm- 

 like larva of caterpiller. Being possessed of a good appetite, it 

 eats the shell from which, it has just issued, and then attacks the 

 substance of the cabbage.'- While small it can eat only the surface 

 of the leaf, but it does this with such assiduity that it soon increases 

 twenty fold in size, and is in a short time able to bite through the 

 entire thickness of the leaf. It is especially active at night, eating 

 then almost continuously, but in the day time it is satisfied with 

 only an occasional meal. Between these periods of feasting it lies 

 quietly stretched along a leaf vein of about its own "diameter, and 

 so exactly does its color resemble that of the cabbage that it is 

 difficult for us to detect it. We can therefore understand that it 

 commonly escapes the eyes of the birds that would think it a dain- 

 ty morsel for themselves or their young. 



