114 THE entomologist's RECORD. 



power ; the transverse ribs show a similar variation. The variation in 

 the elevation or compression of the ribs is another striking character. 



Viewed in cross-section, the egg usually appears to be circular, but 

 sometimes the prominence of the ribs gives it a polyhedral appearance : 

 Doherty says that in the Lycaenid genus Poritia, it is hexahedral. In 

 shape eggs vary a good deal ; those of butterflies are classihed by 

 Scudder as " barrel-shaped, globular, hemispherical and tiarate." There 

 is a general similarity of shape among those of each of the main 

 divisions although this rule is not without notable exceptions. The 

 egg of the NocTU.'E is usually of a hemispherical shape, somewhat 

 flattened at the base ; but that of Xanthia has raised ribs rising above 

 the central point or apex and curving down thereto and it is not unlike, 

 in a general way, the egg of a Vanessa. The egg of the Geojietrje is 

 usually oval or ovoid, but assumes the form of a rather square-based 

 parallelopii^ed in Ennomos (Enyonia) ; the eggs of BrepTios, Alucita and 

 Thyatyra also have the usual Geometrid shape. The egg of the 

 ToRTKiCES has the ajDpearance of a flat scale, but so has that of Lirnacodes 

 testudo and of many Pyralides and other Micros. These examples are 

 sufficient to show that although some general forms hold fairly well, 

 yet that there are striking exceptions. 



The primeval egg was probably ovoid, colourless and transparent 

 and with no sculpturing on the cell wall. This would soon undergo 

 modifications in many directions under need of protection and con- 

 cealment, and it is possible under these conditions that one may find 

 isolated examples of almost any form in any of the families, although 

 the simplest form of egg must generally be found in the lowest families, 

 and no highly-developed structure can occur except among the most 

 highly elaborated families. 



Among the Rhopalocera, the eggs of the various large sub-families 

 are very characteristic ; as, for example, the globular egg of the Papi- 

 lioninae, the nine-pin or spindle-shaped one of the Pierinae, the hemi- 

 spherical one of the Pamphilidi and the echinus-like one of the 

 Lycaeninae. It is also noteworthy that the egg of the Parnassidi is of 

 a somewhat tiarate shape. Superficially, the globular eggs of the 

 Safyrinae are not very unlike those of some PapHioninae ; and one 

 cannot but be struck with the general resemblance between those of 

 certain Nymphalidae and those of the Pierinae; the former indeed 

 appear to form a rough connecting link between those of the 

 Papilioninae and Satyrinae on the one hand and the very tall eggs of 

 the Pierinae on the other. This would appear to indicate a much more 

 intimate relationship between the Pierinae and the Nymphalinae than 

 has hitherto been admitted by systematists. Speaking of Heodes, a 

 Lycaenid genus, Scudder says : — " The base of the egg is broadened to 

 such an extent, that it is only by sufferance that it can be classed as a 

 tiarate egg ; it is rather demi-echinoid." 



The egg-shell appears to vary a good deal in thickness, but this is 

 probably due in part to the thickness of the ridges and ribs with which 

 it is covered. It is thinnest in Vanessa ; delicate in Neineobiiis, in the 

 Pierinae and in some genera of the Satyrinae ; whilst in Lycaena and in 

 the Pampjkilidi it is particularly tough and opaque. 



It may be generally assumed that the eggs of closely allied species 

 are very much alike both in shape and markings. A striking illustration 

 of this is furnished by Vanessa polychloros and V. urticae, the eggs of 



