No. 4-] METAMORPHOSIS OF THE FLAG WEEVIL. iSl 



flag capsules in autumn) quietly within the larval burrow ; eight 

 or more months are spent in hiding in winter quarters ; activity 

 only begins with the season of iris flowering, and lasts for about 

 a month. Opposition continues sparingly after the first week. 

 Except at the beginning of the season, several developmental 

 stages may be taken at the same time, and this fact renders 

 dates of first observation only of value as indices of life history. 

 The more striking features of this life history are : 



1. The small number of larval stages, for a representative of 

 this order. 1 



2. The exceedingly rapid growth during the first period of 

 the third larval stage. That an animal which will live a year 

 should attain the greater part of its growth within a week is 

 indeed a striking phenomenon. To be sure, this growth is mainly 

 increase of fat. 



3. The long period of adult inactivity, extending through two 

 stretches of warm weather. 



The metamorphosis of this beetle is very complete. The 

 segregation of the development life into growth period (period of 

 partial anabolism -- fat-making) and differentiation period is very 

 marked. The transformation of the degenerate larva, lacking 

 wings, legs, antennae, eyes, optic lobes, and salivary glands, into 

 the adult with all these parts well developed, is very rapid. 

 There are excellent reasons for believing that these things have 

 been independently acquired in the order Coleoptera. Inter- 

 nal metamorphosis has as yet been studied only in such repre- 

 sentatives of this order as, in the larval stages, have legs and 

 antennae and eyes, and undergo a metamorphosis much less 

 rapid and complete. Therefore, it should be important to learn 

 whether this increasing periodicity in life history has produced 

 the same changes here as in other orders, whether disappearance 

 of larval appendages has resulted in the internal development of 

 imaginal discs, whether rapid metamorphosis is accompanied by 

 phagocytosis, etc. 



The external signs of internal metamorphic processes begin to 



1 Dr. C. V. Riley found four larval stages in the clover leaf weevil. /'/</, 

 ' The Clover Leaf Beetle Phytonomus punctatus Fabr.," Rept. U. S. Deft, of 

 Agric. for iSSi, pp. 171-179, PI. X. The Phytonomus larva is less degenerate. 



