OP FICUS ROMiTTRGHlI 



maalilo 



in the earlier stages of evolution were readily I(T() ^ hl , - . 



thousand achenes from a mature receptacle containing I 1 "^ 0VCr d 



sown and yielded an enormous crop of seedl* * J ° n ° rcco * niBabld in *"« 



; 





mtect 



Those insects which succeed in forcing their way into 



the recpptacul 



diately set about attempting to deposit their ova within the fw7 n'u CaV " 1< " "" m6 

 about over the surface from one flower to another, and in the case oLll * T? * '" ' 



get rid of their ova, and then die. The site of depositions t !« v" " ™ pi, " > 



between the epidermis and the loose parenchyma, and at a level with """^ 



little bene 



te of attachment of the funicle, and therefore at some distan e beneath flTi 



attachment of the base ofthes t) le (Plate IV, fig, U, 16 ). The deposit,, 1 p X 



take place, not via the style, but by means of penetration of the upper surface of C 

 1 he external ovipositor is certainly too short to reach even the hue of thestv leiu „,,,„ 

 but, without definite information regarding the length to which the internal ortion 

 protruded beyond it, this cannot be regarded as evidence of any great wight in r< 





f till! i\ 



the question. The really important evidence lies in the structural f. it 

 as these show that a very much more direct route to the site of deposition is present bom tl. 

 summit ol the ovary than from the stigma, and one, too, in which the araoun of sou 

 tissue to be penetrated is very much less than in the case of the stylar route. This is shov 

 very clearly by the following measurements 



• 



1 



1. Distance from superior surface of ovary to site of deposition 



Thickness of ovarian wall , q.q i 



nun 



Depth from internal surface of ovarian wall to micropyle, which lies immediately 



below 



0-02 mi 









Depth from micropyle to level where the secundine becomes closely adherent to 



the nucellus . . . 00 







Depth thence to site of deposition . . . • 004 



Total depth from surface of summit of ovary to site of deposition 01 I 



Depth of really solid tissue to be penetrated 08 



mm 







2. Distance from inferior extremity of stylar canal to site of deposition 



Depth of solid portion of style from lower end of stylar canal to inner side of 



inner stratum of ovarian wall 016 mm. 



Depth thence to site of deposit 08 mm. 



Total depth of solid tissue to be penetrated 



02* 



It is evident from the above figures that the stylar route reckoned from the lower 

 extremity of the stylar canal is one-third longer than the other one, and includes three 



times as larce an amount of solid tissue as it does (Plate IV, fig. 19). It i , moreover, 



much more indirect, as will be clearly evident on reference to the drawing, for the upper 

 surface of the ovary lies vertically over the micropyle and the site of deposition within the 

 nucellus, whilst the lower end of the stylar canal is situated far to one side of the latter. It 

 does not thus appear to be the different form of the stigma and style in normal female and 

 gall-flowers, which permits of the deposition of ova in the latter and prevents it in the 

 former. The real determinant is, no doubt, the very great difference in the character and 



thickne 



_ of the ovarian walls in the two cases. Over the summit of the ovary in gall 



flowers the wall is only about a third as thick as it is in the corresponding site ,„ 



