112 BRITISH LBPIDOPTEEA. 



That the details of such an arrangement as this will be modified by 

 further observation is highly probable, but that this will form a sound 

 basis for future work we feel convinced. We shall find, for example, 

 in future schemes, no derivation of generalised from specialised super- 

 families, nor a flat-egged family from an upright-egged one, the 

 former giving rise again to another upright-egged family, as repeatedly 

 occurs in the work of Packard, Dyar and Meyrick. As an illustration of 

 this point we may give the following : Packard derives Lithosiidae (an 

 Arctiid form, with upright egg and Arctiid larva) from Tineina (with 

 flat egg), and then derives the Geometridae (another flat-egged group) 

 from the Lithosiidae. In his work the following series occurs : 

 Tineina (flat egg), Notodontidae (upright egg), Ceratocampidae (flat 

 egg), etc., i.e., a reversion from the " upright " to the " flat " egg form 

 in every alternate stage of the evolution. Dyar, too, obtains the 

 following series in one of his phylogenetic trees : Notodonts (upright 

 egg), Eupterotids (flat egg), Lymantriids (upright), Bombycids and 

 Lasiocampid (flat eggs), an impossible combination. 



The diagram (Plate I) which we have added to illustrate this chapter 

 will show roughly our views as to the evolution of the three main stirpes 

 at their base, and the details of the evolution of the Sphingo-Microp- 

 terygid stirps. 



* American Naturalist, 1895, p. 803. 



