37 
I. Vanessa io.— la Tutt’s first volume on butterflies, io has no 
underside-—not by description. In Newman’s butterflies, the descrip¬ 
tion runs “ the underside is jet black.” 
II. Argynnis selene .—Even hints of sexual dimorphism in their 
undersides are non-existent, or wholly vague and by inference. There 
k marked sexual dimorphism in many localities—probably unfailing 
only in some localities (as Ashdown, where dark brown markings 
may obscure it in the 2 ) occasionally obscured by racial characteristics 
in some individuals. 
If one accepts the prevailing condition of affairs, i.e., until the 
present work of Tutt now in issue, we have to accept it as showing 
that the underside is considered to be much less worthy of observa¬ 
tion than the upper—it is of subordinate importance. On the con¬ 
trary, one is disposed to think that as looked on from the point of 
view of the furtherance of existence and of propagation of the species, 
to the butterfly the underside markings and colouring are more 
important, as a general rule, than the character of the upperside 
markings. That is to say that, in the upperside, departures from the 
normal of the markings of butterflies are less likely to result in 
disasters to the imagines than equally decided aberrations of the 
underside, or adherence to prevailing forms is more essential in the 
case of the underside than of the upperside. 
Restriction of variation of undersides .—Any attempt to deter¬ 
mine whether upperside aberrations are more common, more wide- 
reaching, more subversive of the usual general effect than the 
underside variations, has to be abandoned for want of time and 
other essentials. One’s impression is certainly that on the whole it 
may be said:—On underside, aberrations are less common than 
on upperside (e.y., especially M. aurinia). On underside, aberra¬ 
tions are mostly insignificant as compared with those on upperside. 
On underside, profound aberrations are much less common than on 
upperside. On underside, aberrations are much less diverse than on 
upperside. A further point is that aberrations of the underside would 
probably be found to be much more generic, i.e., of closely parallel 
characters in allied species, than is the case of upperside, where aber¬ 
rations would be found to be more occasionally parallel. 
These impressions may well be useless, being based upon confessed 
insufficient attention generally to undersides. It is well open to 
discussion, and there is plenty to be said. But certain instances can 
be given Polymorphic species with great variation of uppersides 
show subordinate polymorphism of undersides usually, so far as one 
has been able to follow them out, e.y., particularly Hypolimnas bolina. 
Some with less polymorphic variation —Neptis sheppardii, green 
shades and white—scarcely exhibit the variation on underside. On 
the underside of sarpedon, the effects of the polymorphism are much 
less noticeable than on the upperside. In our 2 Lycaenuls the 
variations of the undersides fail entindy to equal in the impressions 
they give the effects of the variations of the uppersides. The same is 
true of Colias, etc., etc. So far, when one has in any species appeared 
to find equal extent of identical variation in any particular on upper- 
and underside, this variation has usually resolved itself into a patho- 
xix. 
