MIMACRAEA. By Dr. C. Aurivillius. 
317 
Btlr. (56 c, d), even the number of the black dots in the basal part of the hindwing beneath is almost 
exactly the same. A fact is that Acraea oberthiiri deviates from the closely allied species ( viviana, karschi, 
cabira and others having only 12 to 14 such dots) by 17 or 18 black dots of the hindwing beneath, and 
that Mimacraea neavei also deviates from all the other Mimacraea known by the more numerous, distinct, 
black dots of the hindwing beneath. But how is this resemblance to be explained? Can it have originated 
from a natural choice ? If we should explain it thereby, we must also be able to explain that it may be of 
great moment in the struggle for existence. Now, the mimicry-theory says that the Acraea are not eaten or 
disliked by birds and other enemies, and that Mimacraea neavei is protected by imitating Acraea oberthiiri. 
Although we assume this explanation to be correct, yet we must ask: would M. neavei not be as well protected, 
if it had only 14 black dots on the hindwing beneath or if the light median band of the hindwing above would 
be somewhat broader or somewhat narrower than in Acraea oberthiiri and not of exactly the same width ? Nobody 
will believe that the birds, before snatching away the butterflies, count the black dots beneath or measure 
the width of the light transverse band. It would be more probable to suppose that the total impression of 18 
dots, compared to that of 14 dots, is so very different that they might be of value in the struggle for life. But 
I can neither believe this, particularly since there are other, very similar Acraea with only 14 or still fewer black 
dots, and which are probably also known to birds as disgusting or venomous. Might it be possible that A. ober¬ 
thiiri is more unpalatable than other similar Acraea and that, for this reason, it is more advantageous to resemble 
it exactly than the others ? This question can only be answered by experiments in nature. If it should be 
answered in the affirmative, it still seems to me that the resemblance between Mimacraea neavei and Acraea 
oberthiiri is too great to be explained merely by the struggle for life. The mimicry is much greater than seems 
to be necessary for deceiving the enemies of the butterflies. This is not the right place for discussing the interest¬ 
ing and much mooted theory of mimicry, but I only wanted to take the opportunity to emphasizing one of 
the numerous problems connected with it, and to give rise to further examinations in nature. 
M. flavofasciata A. Schultze (62 c, d), according to the description, seems to be very closely allied flavofascia- 
to neavei. The short description says: ,,This species, resembling Acraea oberthiiri above and beneath, belongs 
to the group with a light yellow transverse band across the middle of the hindwing beneath; upper surface: 
forewing black with an ochreous-yellow, anteriorly somewhat tapering spot of the posterior margin in the 
areas 1 to 3, being extended in area 1 towards the base, and an ochreous-yellow subapical band in 4 to 6, and 
8, 9; hindwing black with an ochreous-yellow median band of about 5 mm width, distally dentated at the veins, 
running through the apex of the discal cell and covering the base of the areas 3 and 4. The under surface is 
almost exactly like that of M. apicalis. Expanse of wings: 48 mm“. South Cameroon. 
M. krausei Dew. (62 b as krausi). Forewing above black with a yellow subapical band in 4 to 6, 9, krausei. 
and a red demi-band extending from the posterior margin to vein 4, of about 5 mm width and situate behind 
the middle, besides with red spots at the base of the areas 2 to 4, a dentate, red, longitudinal line in the discal 
cell and two red lines at the base of the area 1 b; hindwing above black with a red median band of 5 to 
6 mm width; forewing beneath almost like above, but at the margin with light and dark longitudinal rays; 
hindwing beneath blackish with a lemon-coloured median band of 3 mm width, about 14 large, black basal 
and discal dots, and in the marginal part with black and light longitudinal rays. Near Mukenge in the Congo 
District. 
M. masindae Baker. ,,Forewing brown with a light yellow, broad subapical band near the apex and masindae. 
almost touching the costal margin; a spot on the posterior margin, covering the area 1 a and the base of the 
areas 1 b to 3, is orange-yellow, reaches vein 4 and is from there to the anal angle obliquely cut off. Hindwing 
brown with almost the whole cell (except at the base and at the costal margin) and the whole median area right 
across the middle broadly orange-yellow. Under surface: forewing as above, but in the marginal part with 
dagger-like longitudinal rays like on the hindwings. Hindwing yellowish-grey with 4 basal dots in a transverse 
line and beyond them with 4 other dots in a bow, the two posterior ones of which are close together; the upper 
discocellular vein with a black dot; in the marginal part as far as the cell there are yellowish longitudinal 
rays bordered with grey, and dirty yellow longitudinal lines; a fine marginal line; fringes ochreous-yellow. 
Expanse of wings: 58 mm.“ British East Africa; Masindi in the Budongo Forest. 
M. pulverulenta A. Schultze (62 d) ,,is most closely allied to julvaria, but it differs from it at once pulverulen- 
by the coherent, reddish-yellow transverse band of the forewing being broken up into two separate light areas, ta ‘ 
a large, anteriorly tapering, distally more or less distinctly defined spot of the posterior margin in the areas 
1 to 3, and a small subapical band in 4 to 6 and 8, 9. On the hinclwing the black marginal band is 
proximad very indistinctly defined, and in 3 UU if extends on the internerval folds as far as the discal cell in 
the shape of densely transversely striated rays; in two specimens even the whole discal cell is densely strewn 
with small black scales. In contrast with it, the reddish-yellow ground-colour extends at the proximal margin 
to area 2, resp. area 3 in the shape of a very narrow band between the marginal band and the black fringes. In 
the only $ the subapical band is sulphureous-yellow. Beneath the new species differs from fulvaria only by the 
