ILLUSTRATIONS. 



PLATES. 



Pagtt 



PI. I. — Spots produced by aphides and thrips 'AO 



Jl. — Photomicrograph of sections to show early stages of stigmonose pro- 

 duced by aphid punctures 30 



111. — Photomicrograph of sections to show later stages of stigmonose pro- 

 duced by aphid punctures and thrips 30 



FIGURES. 



Fig. 1. — Cross section through a fully developed spot in a mature carnation leaf. 14 

 2. — Cross section of a carnation leaf several days after it had been i^unc- 



tured by an aphid - 15 



3. — Cross section through the middle of a fully developed spot on a 



mature"Carnation leaf 16 



4. — Cross section through a fully developed spot produced by thrips 19 



6. — Gross section of a young carnation leaf showing an aphid's sucking 



apparatus in the tissues — ■■ 20 



6 



