MUSCA CARNARiA. 329 
the colour and firmness of leather. If 
opened while in its white, soft state, it 
seems to contain only a half-fluid mat- 
ter, in which no trace of the future ani- 
mal can be perceived ; but in a few days 
the form of the fly may be distinguished, 
and in three weeks it becomes quite per- 
fect. 
Lucy, Yet these changes could not 
have been observed through the browu 
leathery skin, as in the case of some 
other insects ? 
Mother, No; the skin is too thick 
for that ; but the person, who dissected 
the fly with so much nicety, was patient 
enough to open one of these egg-shaped 
chrysalids every day, by which means he 
was enabled to trace the whole progress 
and development of the fly. 
Lucy, Mamma, another curious cir- 
cumstance in the changes of this fly is 
the half-fluid matter found in the g^^; 
for in all the other insects, which you 
have described, their shape was distin- 
