101 
Di'. T. A. Chapman on Callophrys avis. 
in any way but as dry objects. Mr. Clark’s observa¬ 
tion on C. avis eggs shows tliat it follows this usual rule, 
and in glycerine it is at once seen that the eggshell has 
two layers—the true shell which is persistent and the white 
coating which disintegrates. His remarkable discovery is 
that in the egg of C. ruhi the adventitious coat differs 
entirely from that of C. avis, in some chemical or other 
. quality, as to be uninjured by Farrant’s medium, and acts as 
if the true eggshell and the coating were one homogeneous 
layer. One would hardly expect so considerable a 
difference to exist between two so closely allied species. 
I ought perhaps to say, though it is carrying coals to 
Newcastle, that I do not report Mr. Clark’s discovery 
without having repeated and verified it m 3 ’^self. As per¬ 
haps having some connection Avith this point, I may 
observe that an egg of C. avis is easily obtained, pure and 
simple, an egg of C. ruhi has nearly always attached to it 
some hairs or filaments belonging to the plant on Avhich it 
Avas laid (see Plate XXIII). A corollary no doubt of the cir¬ 
cumstance that the egg of C. avis is attached merely by its 
base, Avhilst that of C. rubi adheres also, if possible, by 
some part of the upper surface. This is probably asso¬ 
ciated with a different composition of the white coating, 
a difference revealed in another Avay by Mr. Clark’s 
experiment. 
The eggshell of G. ruhi comes out little if at all in¬ 
jured after successive treatment by water, by alcohol, and 
by benzole, that of G. avis is decidedly damaged both by 
alcohol and by benzole, but by Avater it is much altered, 
and the water around it exhibits a multitude of minute 
colourless spindle-shaped bodies of about O'OOl mm. in 
length. 
In all cases, the base, Avhich has no coating, is unaffected, 
and retains its network unaltered. 
Plates XXV and XXVII shoAv the eggshell of G. rubi Avith 
the mesh of ribs arranged in triangles, so that they Avould 
obviously fall into hexagons but for the exigencies of a 
curved surface. The columns are end on, and so do not 
.^ihoAv their height. The double outline of the ribs is, no 
doubt, an optical effect in the dry shell of the empty egg ; 
it is seen also in G. aws and in other Lycaenid eggs. Fig. 2 
is a portion of the eggshell of G. avis dry, and not 
pressed. 
In Plates XXVI and XXVII Ave have three specimens of 
