ORDER LEPIDOPTERA 



61 



Sap-faeding Instars 

 Tissue-feeding Instars 

 Mixel-feeling Instars 

 Non-feeding Instars 



Pupa 9 



Fig. 25. Diagram of leaf-inhabiting stages in certain Lepidopterous 

 larvae. Read from the bottom upward; it is also a diagram of progressive 

 adaptation. The upper half of it represents the Gracilarian (sap-feeding) 

 series. Line 1 represents Phyllocnistis only. Line 2 represents typical 

 conditions among the second (Cameraria) group of Lithocolletis — the 

 group with fiat larvae. Line 3 represents the first (typical) group of 

 Lithocolletis larvae (except L. ostensackenella) . Line 4 represents Leucan- 

 thiza, and Apophthisis, and typical Acrocercops. Line 5 represents 

 Gracilaria (in part), Parornix and others. Line 6 represents Paralechia. 

 Line 7 represents Proleucoptera, Leucoptera, Lyonetia, Aphelosetia, 

 Cycloplasis, and others. Line 8 represents Nepticula (teste Miss Braun). 

 Line 9 represents Nonagria and others. Line 10 represents Arzama and 

 others. Most important of the others in the last two cases (lines 9 and 10) 

 are two large genera whose species are not quite uniform in leaf-mining 

 instars: Bucculatrix, whose larvae later feed openly upon the leaves, and 

 Coleophora, whose larvae later are mainly case-bearers. The diagram is 

 not exact; it is intended only to show the general trend in evolution of the 

 leaf -mining habit. 



