MUSCA TENAX. 821 
Mother, There are a few instances of 
ehrysalids being endowed with the power 
of moving to a certain degree ; and yoiL 
know there are several genera of in- 
sects, particularly in one order, where 
the nymph is as active as the larva, 
and seems to differ but little from the 
imago. 
Luci/. Oh yes, I recollect ; the cricket 
and the grasshopper. But those in- 
sects, which change within a pupa case, 
and lie concealed for a long time, 
could make, I think, but little use of 
horns. 
Mother. There are some pupae, which 
can advance, though unable to move 
backwards. I think I have already men- 
tioned the chrysalis of the goat moth, 
which has horns along its back; these^ 
horns, by acting against the bark, under 
which it lives, assist it to move forward,, 
but prevent its retreating. 
Lucy, I had quite forgotten this ;. 
but 1 believe you only mentioned it 
p 6 
