264 NATURE-STUDY REVIEW [13:6— Sept., 1917 



the construction of the cocoon like the ribs of a basket. Watch 

 the weaving pattern. It changes gradually as the spinning pro- 

 gresses. For a little amusement force the larva when nearly spun 

 up to defend itself. It may plunge its jaws through the cocoon and 

 attack a pair of tweezers fiercely. Or tear the cocoon and watch 

 the larva carefully mend it so that the tear can scarcely be found. 

 The cocoon when completed is about the size of a pea and, as many 

 writers have remarked, appears to be about half the size of the 

 original larva though it is now contained within it. 



Within this cocoon, the larva transforms to the pupa, the resting 

 stage before that of the adult. One can follow the changes by the 

 external appearance of the cocoon. The black disc at the lower 

 end of the cocoon indicates that the larva has molted and now there 

 is a pupa within. As the pupa matures, a distinct greenish tinge 

 can often be seen in the cocoon and sometimes the dark eyes of the 

 adult are evident. 



Finally after about two weeks, the pupa pushes off a circular lid 

 at the upper end of the cocoon and emerges. This lid by the way, 

 is the result of certain weaving of the larva while spinning and is 

 not cut by the heavy pupal mandibles. The pupa in this case is 

 the adult with a transparent skin over it. The pupa immediately 

 seeks to climb and if it be placed on a potted plant, it will climb 

 rapidly up a stalk, take up a position at the top with the head 

 upwards and then begin a series of expansions which are calculated 

 to burst the pupal skin and free the adult. After ten cr fifteen 

 minutes of expansion the body will be shifted forwards and this 

 bursts the skin over the thorax. The adult slowly emerges, then 

 takes up a position again with head uppermost to allow the wings 

 to expand. These expand by blood pressure, the tip being the last 

 to flatten out. Immediately after the wings are expanded, the 

 adult voids a large lump of excrement which one can see as a black 

 area near the end of the abdomen. This is the excrement stored 

 up by the larva through its whole life as the intestine of the larva 

 does not extend entirely through the larva so it can not be voided. 



The adult will now attach plant lice and eat three to a dozen at a 

 time. The light green coloration of the adult is a very good exam- 

 ple of protective coloration. This color very closely matches that 

 , of the leaves among which it rests during the larger part of the 

 day. The adults have an important means of defense. When 

 they are disturbed or squeezed between the fingers, they emit a 



