288 TfiE entomologist's RECORl). 



in Noctuids, in Arctiids, Lithosiids, Liparids, Chloephorids, and some 

 others. This grouping of the butterflies can only be objected to by 

 those who still regard them as a group of phylogenetic and classifi- 

 catory value equal to all the rest of the Lepidoptera, but there is no 

 doubt that their value, as a group, is merely that of one of a con- 

 siderable number of groups. 



If all these groups with vertical eggs are related, to the exclusion 

 of those with Hat eggs, we should expect to find some other character 

 in common, which does not occur in the flat-egged groups. Doubt- 

 less there are a number of such characters, but the one I have been 

 most struck by is that of the possession by the larvte of some species 

 of that very peculiar organ, the chin -gland. I have not been able to 

 hear of any flat-egged species possessing a chin-gland, yet it occurs 

 in many species of the Butterflies, the Notodonts and the Noctuids, 

 the three groups that are perhaps most in need of a confirmatory 

 common character. 



Since the Hesperides are a very low group of Obtect^e, it follows 

 that the vertical egg and the chin -gland must have been established 

 characters at an early stage of evolution, before the Heterocerous 

 groups separated from the Rhopalocerous, and probably before they 

 were definitely Obtect^. 



When we look at the eggs of the butterflies as a group, we find 

 that the Hesperids and Papilionids have eggs which are simple and 

 smooth, with sculpturing, when at all definite, tending to a hexagonal 

 pattern. In the higher groups they tend to more elaboration. In 

 the Lyctenid.e they retain a more or less hexagonal network. In the 

 PiERo-NvMPHALm^ they reach a pattern of primary vertical ribbing 

 and secondary transverse ribbing, the hexagonal nature of the cells 

 so formed being, however, usually more or less distinct. It is, in 

 fact, rare to find the transverse ribs continuous across the primary 

 ones, they usually alternate between each rib. I cannot at present 

 certainly call to mind an instance without reference to my note-book. 



When we come to the Macro-Heterocera with vertical eggs, we find 

 a similar progression from the Notodonts, whose eggs are often not 

 dissimilar to those of Hesperids, to Arctiids and Liparids, Avhich have 

 an obscure hexagonal pattern, but are usually rather smooth, and to 

 Noctuids, which are parallel in their sculpturing with the Piero- 

 Nymphalids. All these vertical eggs, no matter how much they may 

 vary in height, whether they be tall and narrow, or short and sqiiat, 

 are circular in a horizontal section, one namely that is parallel to the 

 base and transverse to the micropylar axis. There is a definite 

 micropylar axis, a, biit the second and third axes, b and c, are in no 

 definite position, and are equal to each other. When we come to the 

 flat or horizontal egg, the micropylar axis, a, is not vertical to the base, 

 but parallel to it, and there are two other axes, h vertical to the 

 surface of attachment, and <• parallel to it, but at right angles to the 

 other two. These axes, b and c, are usually of difierent lengths, and 

 when they are equal, are so, one might say, accidentally, rather than 

 necessarily. The groups that present this form of egg appear to fall 

 into two sections, the Bombycid and the Geometrid, These divisions, 

 though not always very easy to distinguish, and equally difficult to do 

 so by the eggs, still present in the Geometrid section more frequently 

 than in the Bombycid, a harder, rougher egg, and one in which the 

 micropylar end is decidedly narrower than the opposite one. 



