INVEETEBRATA, CRYPTOGAMIA, MICROSCOPY, ETC. 86/ 



There is no doubt that these markings are due to filaments which 

 are elevated on the inner side of the upper membrane, and appear from 

 the exterior as fine stria3. In the large scales of Costnia it can be seen 

 very clearly that they do not entirely traverse the interior of the 

 scale, but terminate free, leaving an interval between them and the 

 lower membrane. 



The latter presents internally a completely difierent structure. 

 There are a great number of small, irregular, transverse lines (some- 

 what similar to those on the palm of the hand), showing none of tho 

 regular arrangement of those on the upper membrane. 



According to M. Deschamps and other observers, the intervals 

 between the longitudinal lines are divided regularly by transverse 

 ones, thus forming small squares, giving the scales a trellised appear- 

 ance, and originating many errors in regard to their true structure. 

 Exact observations, however, on scales in which the two membranes 

 were dissected apart, have shown that this is a deception, and that the 

 appearance is produced by the lower set of striaB showing through the 

 upper transparent membrane. 



Dr. Burmeister's views are, we need hardly say, opposed to those of 

 Mr. Beck,* and would appear to bo disproved by his well-known 

 experiment of running moisture up and down in the furrows between 

 the " corrugations " on the under surface of the scales. 



Butterflies with Dissimilar Sexes-t — Mr. Meldola has an inter- 

 esting review of Fritz Miiller's paper in ' Kosmos,' on this subject, 

 the phenomena of which have been well described by Mr. S. H. 

 Scudder, under the name of " Antigeny." The princijial object of 

 the author is to show that in some cases the male, and not the female, 

 is the selecting partner. Dealing with Epicalia acontius, of which the 

 sexes are so separate that they have been placed by some systematic 

 zoologists in even difierent genera, while Fabricius applied the 

 specific name of AntiocJius to the male and of Medea to the female ; 

 the author shows what is the extent of the dilference by describing 

 what obtains in the two sexes ; in both sexes the general ground colour 

 of the wings is black, the male has a broad oblique bar of a bright 

 orange colour extending from about the middle of the inner margin 

 of, to about the middle of the fore-wing in the direction of the apex ; 

 as there is a corresponding blotch near the middle of the hind-wing, 

 the whole furms, when the wings are extended, one oblique orange 

 bar ; now, the female has two oblique rows of pale yellow spots across 

 the fore-wings, which run nearly parallel with the costal margin, 

 and there are two similar rows across the hind-wings, and these, with 

 extended wings, give rise to the appearance of three straight parallel 

 rows (which are continued on to the body by spots of the same colour). 



It is to be noted that the hindmost row of spots " have been dis- 

 torted so as to form a straight bar parallel with the other rows ; this 

 results from the displacement of the spots, each of which, although 

 situated in one wing-cell, does not appear on the corresponding place 

 in each cell ; were this the case, the row would be curved instead of 

 straight. That it was the sense of beauty of a critical eye, which 

 * See ante, p. 810. t 'Nature,' xix. (1879) p. 586. 



3 M 2 



