APPENDIX. ' 295 



nation of several square feet of soil aud grass under different trees which 

 tad borne or had had wormy apples sorted under them; no trace of the 

 insect was found. 



If the worms are carried into the storeroom oi* barreled with the fruit 

 when it is picked, upon leaving the apples they spin their cocoons in the 

 crevices and angles of the barrels, or anywhere in the storeroom, especially 

 in any rags, papers, or clothes that may be lying about. 



How it ii> nudh — Having found a suitable place, the apple worm first usually 

 hollows out with its jaws a little oval cavity, and then begins its cocoon. 

 The cocoon is rather thin but quite tough and is made largely of silk in 

 which are mixed bits of the substance on which it is being made. It is lined 

 with a thin layer of white silk, and on the outside it is usually covered, and 

 often thickened at some point, with more loosely bound together particles of 

 the surrounding substance ; this renders the cocoon quite inconspicuous. 

 Several cocoons are shown, natural size, in Fig. l.'}"), just as they appeared 

 on the piece of bark when it was removed from the tree. Fig. 136 shows 

 some cocoons enlarged, and it well illustrates their method of construction. 

 In shape, the cocoons are adapted to the shape of the place in which they are 

 l)uilt. Anyone can soon find these cocoons on old rough-barked apple trees 

 after a little search at almost any time from August 1 until spring opens. 

 <. 'ooke states that a worm completes its cocoon in twenty-four hours. It is 

 said that the cocoons made by the worms late in the season, and in which 

 they expect to pass the winter, are tougher, thicker, and darker colored than 

 those made earlier, from which the moths soon issue. 



HOW LONG AND IN WHAT CONDITION THE INSECT LIVES IN ITS COCOON. 



Usually when the cocoon is made during or after August, the insect may 

 be found therein as a caterpillar until the next spring. If the cocoon is 

 made before August 1, its maker, the caterpillar, may change within three 

 days to a very different looking object known as pupa. Cocoons containing 

 these pupa* are shown, natural size, in Fig. 135, and enlai'ged in Fig. 13(). 

 The insect usually spends but two or three weeks, sometimes less, in the 

 pupa state, whether the change to a pupa takes place in July or not, until 

 the next spring. Thus the insect may spend less than three weeks of its life 

 as a pupa in the cocoon, or it may occupy it as a catei'pillar for ten months, 

 and then as a pupa for two or three weeks longer. The reason for this 

 seemingly great variation in the life-history of the codling moth will appear 

 in the discussion of the next and very important phase of the subject. 



THE NUMBER OF BROODS OF THE INSECT. 



For more than a century the statements which have been made regarding 

 the number of broods of the codling moth during the course of a year have 

 differed widely. Some writers record only one brood, others two, and some 

 as many as three or more in a year. This variation has been the subject of 

 considerable discussion in Germany, and more recently in the United States. 



Beginning with' Goedart's tirst account in 1035, the European records 

 indicate but one brood north of latitude 50 degrees, that is, in England, 



