516 TRANSACTIONS OF SECTION D. 
However, the weight of evidence seems to show that melanism in lepidoptera 
frequently follows the Mendelian law of heredity and in most cases is dominant, 
but in some few species seems to ibe recessive. 
3. The Correlation of Pattern and Structure in the Ruraline Group of 
Butterflies. By G. T. Beruune-Baxer, F.L.S., F.Z.S. 
An exhibition was made showing changes in pattern, colour and structure 
in nearly allied genera in the Plebinz, Strymonine, and Ruraline, also showing 
similar changes among species in the genera Plebeus and Ruralis. A further 
exhibit was also made of a few species of the genus Acrea, showing specimens 
that are very different superficially in colour, but their structure is very close ; 
also showing other specimens where the pattern is very close, but the structure is 
very different. It must be borne in mind that as there are both generic and 
specific resemblances, so there are generic and specific differences, but they do 
not necessarily pass along parallel lines. Apparently small changes in pattern 
may be accompanied by a marked difference in structure, whilst a marked 
divergence in colour may be accompanied by a very slight change in structure. 
The latter, however, would probably be a specific rather than a generic differ- 
ence. In the Ruraline the tegumen of the male armature is of dominant generic 
value, as also would be a great divergence of the aedoeagus or the harpagines: 
but small mutation in the two latter organs might merely indicate specific rather 
than generic difference. 
So far as this special group of butterflies is concerned, there is no question 
on the point that change of structure is accompanied by change of pattern, or 
change of structure accompanies change of pattern. Reviewing all the data, 
the latter is probably correct, for colour and pattern seem more sensitive to 
mutability than structure. This shows itself particularly in the genera Ruralis 
and Heodes. In the former there are species that are brown, orange colour, blue, 
and metallic lustrous green, whilst the undersides follow two special lines of 
pattern. But it is scarcely possible to divide the genus, as the neuration and 
male armature prevent this being done. In the genus Heodes there are species 
of brilliant lustrous golden copper colour, and also of lustrous purplish. Here, 
again, however, the neuration is the same; but the male armature is evidently 
undergoing a certain phase of evolution. So that, though it may not be possible 
to divide the genus to-day, it is probable that ere long that will have to be done. 
Other genera of butterflies that I have examined also bear out my contention. 
We have both the great genera Papilio and Charaxes, that naturally group them- 
selves into sections, so far as their colour and pattern are concerned, this group- 
ing being also followed considerably in their structural details. I am therefore 
led to believe that pattern is very generally correlated with structure in butter- 
flies. 
4. The Enemies of ‘ Protected’ Insects; with Special Reference to 
Acrea zetes. By Dr. G. D. H. Carpenter. 
Supporters of the theory of mimicry believe that certain insects escape being 
eaten by vertebrates generally on account of distastefulness, the possession of a 
sting, spines, &c. Such are said to be protected insects. This is not meant to 
iraply protection against every enemy, or even against every vertebrate enemy. 
Such a state of affairs would soon bring itself to an end by the unlimited increase 
of such an insect. There is evidence that bee-eaters, for instance, prey especially 
upon such a typically protected insect as the honey-bee; that cuckoos prey 
especially upon hairy caterpillars shunned by other birds. But the enemies of 
protected insects that are of much importance are predaceous insects and 
parasites. I have seen in Uganda insects belonging to typically protected 
groups (Hymenoptera, Hemiptera, &c.) being preyed upon by predaceous insects. 
Since of all the offspring on the average only two individuals will survive to 
carry on the race, insects which escape vertebrate enemies must be all the more 
destroyed by parasitic or predaceous insects. In the case of Acrwa zetes—a 
typically ‘protected ’ butterfly—out of seventy full-fed larve and pup obtained 
in Uganda, only sixteen, or 23 per cent., became butterflies, 77 per cent. being 
