84 



Undoubtedly there are other reasons than those of mere conven- 

 ience which have so impressed themselves upon the inherited experi- 

 ence of the weevils as to lead them to the choice of this position and 

 the consequent location of the punctures and eggs. Most apparent 

 of these reasons, and probably also most important, is the advantage 

 which this location affords in the protection of the eg^ and the young 

 larva developing from it against the attacks of natural enemies as 

 well as from the injurious effects of drying and deca}^ 



This protection is readily explained by several facts. The place 

 chosen is through the thickest and toughest portion of the floral 

 envelopes through which the anthers can be reached, since the thick- 

 est parts of both calyx and corolla are toward their bases. More 

 important than the thickness of the layers of vegetable matter is the 

 character of the tissues through which the puncture passes. Though 

 corolla and calyx are both modifications of original leaf tissue, both 

 have changed so greatly in form and texture that the resemblance is 

 recognized only by those somewhat acquainted with plant structure. 

 The corolla, moreover, has changed far more than has the calyx, and 

 in becoming so highly specialized its tissue has lost certain . powers 

 still retained by the green calyx tissue. The particular power referred 

 to in this connection is the ability to heal small wounds. Punctures 

 made in the corolla must, therefore, remain open, while small punc- 

 tures through the calyx will in most cases be healed by the natural 

 outgrowth of the tissue, so as to completely fill the wounds in a man- 

 ner entirely analogous to the healing of wounds in the bark of a tree. 

 The custom of the weevil of sealing up its egg punctures with a mix- 

 ture of a mucous substance and excrement is of great advantage and 

 assistance to the plant in the healing process. While undoubtedly 

 applied primarily as a protection to the egg, it serves to keep the 

 punctured tissues from drying and decay, and thus promotes the 

 process of repair. 



As a result of the growth thus stimulated in the calyx, the wound 

 is perfectly healed in a short time, and, as is the case in the healing of 

 the bark of trees, here also we find a corky outgrowth projecting above 

 the general surface plane. This prominence the writer has termed a 

 ^Svart" (PL XIV, fig. 65). The healing is completed even before the 

 hatching of the egg takes place, and thus both egg and larva partake 

 of the benefit of its protection. 



It is possible for the puncture to heal without the full development 

 of the wart, and it is also possible for eggs to develop successfully 

 even when the puncture was made through the corolla alone and no 

 wart developed, but in the latter case the chances are rather against 

 it. Occasionally warts do develop from feeding punctures which were 

 small, but the exact conditions under which this takes place have not 

 been determined. 



