198 



PTILOTA. 



furnished Avitli the rudiments of wings. This division, there- 

 fore, corresponds with the section Pupa semi-completa of 

 Linnseus, or the Metamorphosis semi-completa of Fabricius. 



The Hemiptera, Orthoptera, and many Neuroptera, under- 

 go this kind of transformation ; but amongst the latter there 

 are some — and they are chiefly aquatic, such as the di-agon- 

 flies and may-flies — which are furnished mth anal or lateral 

 plates or gills for breathing in the water : these, therefore, 

 require to be formed into a distinct division, the preparatory 

 states bearing in fact less resemblance to the imago than 

 those species which are terrestrial in their larva and pupa 

 states, breathing by spiracles, and greatly resembling the 

 imago. As it is evident, however, that the latter undergo a 

 less decided metamorphosis than the former, we must place 

 the species which have the more decided semi-complete pupa 

 at the head ; indeed, Mr. MacLeay has separated the others, 

 and applied to their changes the term metamorphosis sub- 

 semi-completa. 



Rgs. 32, Larva— 33, Pupa— 34, Imago of Ephemera vulgata. 



The third or total metamorphosis {Met. perfecta of La- 

 treille) consequently consists of the Linnaean groups having 

 incomplete, obtected, and coarctate pupse. These are to be 

 regarded as separate divisions. Amongst these pupae some 



