^^ AND ^^^^ 



JOURNAL OF VARIATION. 



No. 6. Vol. V. June 15th, 1894. 



I'lie Life-jJistory of a Lepidopterous Iiisect, 



Comprising some account of its Morphology and Physiology. 

 By J. W. TUTT. F.E.S. 



(Continued from page 115). 



Chap. II. 

 THE OVUM OR EGG. 



2. — On variation in eggs. — Everything in nature varies, and there 

 can be little doubt that there is as much variation in tlie eggs of Lepi- 

 doptera as there is in their larva3, pupa3 or imagines ; comparatively 

 little attention has however as yet been devoted to the subject. So far 

 as observations have been made, they show that not only do the eggs of 

 diffei'ent species differ from one another, but also that there is variation 

 in the eggs of the same species ; this may affect either shape, size, 

 colour or ornamentation. 



a. Shape. — Eggs do not always retain the shajDC which characterises 

 them when tirst laid. Scudder figures the eggs of two species of Eurymns 

 ( =: Colias) with flattened bases, whereas the egg of CuUas is really remark- 

 ably spindle-shaped, tapering rapidly to both ends. Buckler gives two 

 descriptions of the egg of Colias hyale ; in one he says " the egg is 

 like a canary-seed in miniature ; " in the other, " the egg is of a long 

 f usif(jrm shape, one end conical, the other knobbed, or like a bag tied 

 round the neck ; " both of these are probably correct. When first laid 

 the egg is very soft, and in some cases, looks as if it were almost fluid. 

 Eggs laid on glass apply themselves to it, and have a very regular and 

 almost perfectly circular or oval outline, but if laid on a leaf or other 

 irregular surface, they apply themselves to its irregularities and become 

 themselves irregular, both in relation to the surface to which they are 

 applied and also as regards their disturbed outlines. Dr. Chapman in- 

 forms me that this irregularity was very evident in eggs laid l)y a Sropnla 

 decrepitali)^, which he forced to lay on the deeply furrowed leaves of Ten- 

 crium. The egg of Colias has distinctly, as has just been observed, a very 

 spindle-shaped outline, and is usually very slender, and very j)ointed at 

 the summit. There would appear to be a tendency when the egg is ap- 

 plied to a leaf under exceptional circumstances, for its }»asal part to spread 



