EGGS OF BUTTEKFLIES. 



lay her eggs. On the other hand, some will fly rapidly from plant to 

 plant when on egglaying intent without much delay, and especially is 

 this the case where the species is local and the foodplant abundant, 

 e.g., Poly om matus bellargus, etc. 



CHAPTER III. 



EGGS OF BUTTERFLIES. 



Lepidoptera are holqmetabolic insects, i.e., they are insects that 

 have a complete metamorphosis, assuming in turn, the egg, larval, 

 pupal and imaginal stages. The eggs of butterflies are naturally of 

 small size, and photographing them has added much charm to the 

 description of these beautiful objects. Under an ordinary lens much 

 of their remarkable beauty may be discovered, but for a proper appreci- 

 ation of their lovely forms, delicate sculpturing and detailed structure, 

 a good microscope is necessary. The egg itself is a cell, consisting of 

 an outside shell, enclosing the living protoplasm which is, at first, 

 homogeneous; the shell is a thin, elastic pellicle, often transparent, 

 and, when opaque, usually made so by the ribs that longitudinally 

 and transversely cross its surface, although, in some cases, as in some 

 of the Urbicolids, etc., there is a general thickening of the wall. The 

 butterfly egg is of the " upright " type, i.e., it has its micropylar axis 

 perpendicular to the surface on which it is laid, whilst its transverse 

 section (at right angles to the microp}dar axis) almost always forms a 

 circle (the only exceptions known being those of the Thymelicids), and 

 its base is almost always flattened at the point of attachment. At the 

 apex or point opposite the base, a number of microscopic canals lead 

 into the interior of the egg ; these canals are surrounded by a rosette 

 of tiny cells, tbe whole structure being termed the micropyle. 

 Through these little canals the spermatozoa pass to fertilise the egg. 



In all the species of any given family, the eggs are almost always 

 very similar, although the details vary in each species. The Thymelicid 

 eggs are " flat " in outline, with three axes of different lengths, whilst 

 all other butterfly eggs have a horizontal section that is circular ; 

 the Urbicolid (sens, rest.) skipper eggs are somewhat more than 

 hemispherical, those of the Lycamids are shallow, flattened, tiarate 

 or echinoid in shape, those of the Papilionids and some Satyrids 

 almost globular, of the Pierids, long, slender and spindle-shaped, 

 of the Nymphalids somewhat barrel-shaped, with projecting ribs 

 reaching from apex to base, of most of the Satyrids cylindrical 

 or spheroidal, etc. The barrel-shaped egg is sometimes more or 

 less conical, and it is usually rather broader at the base than at the 

 summit. The surface of the egg may be practically smooth, reticu- 

 lated with a surface sculpture, or ribbed longitudinally from base to 

 apex, and often with finer transverse ribs running round and crossing 

 the longitudinal ones. These various modes of sculpture run into one 

 another, and are often not sharply defined, and in the Lycamid and 

 Limenitid eggs the sculpture forms patterns and traceries of exquisite 

 beauty. The ribbing generally fades off into the micropylar area, 



