DESCRIPTION OF PLATES. 



Plate I. 



Kg. 1. Normal caterpillar for contrast with fig. 5. 

 „ 2. Portion of highly diseased caterpillar showing pebrine spots — especially note 



those on the anal horn, which frequently has a scorched appearance. 

 „ 3. Highly diseased moth showing distorted, crumpled wings. 

 „ 4. Piece of skin of caterpillar with pebrine spots, treated with caustic potash and 



examined under a microscope. Each spot is a little " cyst " of pebrine spores. 



The younger ones are smaller and lighter coloured. 

 „ 5. Highly ^diseased caterpillar showing pebrine spots. 



Plate II. 



Tig. 1. Portion of silk gland of highly pebrinised worm — the white patches are infected 



areas. 

 „ 2. Portion of the gut of a caterpillar fed heavily on spores and thus heavily diseased 



showing black spots on the gut wall — comparable with pebrine spots in the 



skin. 

 „ 3. A section through the skin of a heavily diseased worm with pebrine spots. The 



blue layer is the outer skin (cuticle) — the pale green is the hypodermis — the 



dark green is muscle — the red masses are foci of pebrine infections — the 



brown masses are old foci of infection which have been infiltrated with ohitin. 

 „ 4. A younger stage in the formation of pebrine spots showing a focus of pebrine 



infection in the hypodermis becoming infiltrated with chitin. 



Plate III. 



.Pig. 1. Early stage in infection of gut wall showing a few spores (oval black) near the 

 basal membrane and a number of meronts, smaller oval bodies each dividing 

 into 2 — note the 2 nuclei in each. Semi-diagrammatic X roughly about 375. 



„ 2. Section through a developing egg showing meronts of Nosema bombycis in the 

 yolk. Slightly diagrammatic X roughly about 375. 



.„ 3. Section through the gut of a caterpillar four days after feeding it on spores, show- 

 ing the extremely heavy spore formation. Note also the digestive juice buds 

 being budded off. Semi-diagrammatic x roughly about 375. 



„ 4. Spore with polar filament extruded X 2150. 



„ 5. Planont just escaped from spore case X 2150. 



„ 6. Planont X 1920. 



Plate IV. 



Diseased moth's progeny fed 4 meals a day bush mulberry. Just previous to spinning- 

 Note great variation in size. 



Plate V. 



Diseased moth's progeny fed 6 meals a day bush mulberry. Just previous to spinning. 

 Less variation in size. 



Plate VI. 



Diseased moth's progeny fed 6 meals a day tree mulberry. Just previous to spinning. 

 Hardly any variation in size. 



( 164 ) 



