Zygena Trifolii. 419 
to the various forms which Procris Statices assumes in 
different localities, but still we do not feel at liberty to 
state that any new species of that genus have been added 
to our lists, further series of specimens from various 
localities are necessary; it may be, that in an insect so 
local and so gregarious as a Procris, each little tribe or 
colony will be found to differ more or less from other 
tribes or colonies of the same species.” 
These remarks apply with equal force to the Zygene 
but since we do allow more than one 5-spotted native 
species, it follows that whether or no Zeller’s theory is 
the true one, a certain amount of constant variation 
among these little tribes, will suffice to elevate it into a 
presumptive species. If such a constant variation were 
confined to one little tribe or colony, and not found else- 
where, I presume such a colony would be considered a 
local form of the nearest allied species, but if it can be 
shown, as I intend to endeavour to do, in the present 
paper, that an exactly similar constant variation occurs 
im numerous colonies in various parts of England, and 
that such constant variation is not confined to the imago, 
but is also found in the respective larvee, such colonies 
or tribes surely have acquired an equal right with Loni- 
cerce to appear in our lists as ‘species.’ 
The chief points by which we can differentiate these 
imsects, are— 
(1.) The size and disposition of the red spots on the 
fore-wings. 
(2.) The black border to the hind-wings. 
(3.) The antenne. 
(4.) The time of appearance of the perfect insect. 
(5.) The larva. 
(6.) The food-plant. 
(7.) The habitat. 
The first two of these points are in some species most 
variable, in others tolerably constant; the antenne aid 
the determination considerably, when the one sex in one 
species is compared with the same sex in another, but I 
have too often seen in collections a series of males 
marked “ Trifolii,” and the females with their slenderer 
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