Pliylogeny and Ecolution of the Lepidoptera. 581 



stirps, in which flat eggs are the rule, has a remarkable 

 eggy which is distinctly upright, and proves the transition 

 from one form to the other not to be difficult at this point. 

 It also shows that families with upright eggs may have 

 more points of origin than the one apparently common 

 to butterflies and NoctuEe. 



The Chloephoridai have also an upright egg; the 

 vertical axis is extremely short, the general form being 

 an exaggei'ation of the very depressed egg of the 

 Acronyctas ; but the ribbing is of a different type, it does 

 not fall in line with the Nochia;, still less with Liparids 

 or Arctiids. The larva and pupa also suggest differences 

 difficult to seize and impossible to put into description; 

 that is to say, that they agree with, say Nocture, in any 

 point I can put into words, and yet leave me with the 

 impression that there is a fundamental difference. If 

 this be a correct impression, there is no doubt some 

 feature capable of observation and description that I 

 have overlooked. 



The N'jctuie have a spherical egg, ribbed vertically and 

 with secondary transverse ribs. I do not know any egg 

 that departs widely from this ; Acronyctas are probably 

 the extreme as to flatness. In some few the ribbing is 

 obscure, apparently from being lost again. This egg is 

 essentially the same as the Fiero-ni/viphalid egg amongst 

 the butterflies ; that the higher development of the 

 upright egg in each of its two great branches should 

 be so similar is remarkable. We have already noted that 

 the Geometrid e^ra- tends in the same direction. ITie 

 greatest difference is that the Noctua egg tends to have 

 the micropylar axis shorter than the transverse (Acro- 

 nycta, etc.), whilst the Piero-nymphalid egg tends to have 

 it longer in nearly all groups. 



The Arctiid egg is nearly spherical, smooth, and 

 polished, with a netted surface very faintly marked. 



The Liparid egg is not unlike the Arctiid, but with a 

 denser texture, duller surface, and often with a depre>sion 

 at the summit. There is greater variation here than, 

 say, in the Noctua. PiuUbunda egg might almost 

 be a Notodonta. Monaclui is very like an Arctia. 

 Salicis is enveloped in a curious foam-like gum, and 

 one is not prepared to refuse a place to Goryli, 

 Ludifica, and some others, although their eggs are 

 distinctly Noctuan. 



