OBTHOPTERA. 
215 
is technically called semi-complete — that is to say, the 
changes in external form, which they undergo in their 
transition from one state to another, are only half so 
considerable as those which take place in some other 
instances — the Lepidoptera for example. In fact, it 
is difficult, in many instances, from inspecting an in- 
dividual to say what stage of its progress it has 
reached. The final state, however, may usually be 
determined by the full development of the wings and 
tegmina ; these members exist in the pupa only in 
a rudimentary condition. The pupa is never quiescent, 
but moves about and takes food. Not only do the 
larva and pupa resemble the perfect insect in exter- 
nal appearance, but it is likewise found on dissection 
that their internal organisation is similar. In the 
penultimate and antepenultimate states, the sexes are 
likewise distinct, and copulation sometimes takes 
place, but it is improbable that this premature union 
ever proves productive. The transformations in 
question, therefore, must be considered as merely a 
series of gradual approaches to perfection, none of 
the transitions being marked by any decided change 
of general form, the only consequences resulting from 
ecdysis, or casting of the external crust, being in- 
crease of size, slight development of certain parts, 
and an aptitude to continue the species. 
This order is one of the least numerous in species. 
But its poverty in this respect is in some measure 
compensated for by the great amount of individuals 
of the same species, the swarms of locusts, grass- 
hoppers, and cockroaches, which sometimes congre- 
