538 
BEES AND BEE-KEEPING. 
make the latter fact apparent ; but the larvae, on 
the contrary, so change in appearance soon after 
infection, that a practical eye at once detects the 
presence of the pest. Whilst healthy, their bodies 
are of a beautiful pearly whiteness, and their skins 
are tense with fulness ; but where the disease strikes 
a larva, it moves uneasily in its cell, often then 
presenting the dorsal surface, as shown at A, Plate I., 
which well delineates a comb in a bad condition. Mere 
posture is thus no insufficient evidence of an unhealthy 
condition. The colour now changes to yellow, or 
the faintest buff, distinguishable immediately in a 
healthy brood-patch, which is, normally, perfectly 
even in tone. The colour strengthens to a pale 
brown, whilst the skin becomes flaccid and opaque ; 
death soon occurs, when the body, shrunken by 
evaporation, lies on the lower side of the cell, becoming 
progressively darker, until it almost assumes the 
colour of coffee; desiccation continuing, in a few 
days nothing more than a flattish, black scale remains. 
In an infected stock, these can be seen in number by 
looking over the comb, having its upper edge towards 
the face of the observer. 
Should the larva escape contamination until near 
the period of pupahood, it is sealed over in the 
normal way. The cover furnishes a screen, on which 
part of the cocoon is soon after spread ; but the in- 
habitant of the cell is marked out for death, and 
before very long the capping or sealing sinks, becoming 
concave, and in it punctures of an irregular character 
appear (A, Plate I.), which is nearly a conclusive 
sign of the diseased condition of the colony. 
