38 



transverse being from a twenty-thousandth to a ten -thousandth. In 

 the scale (fig. 10), the longitudinal stria? are a thirteen-thousandth, 

 and the cross stria? a thirty-thousandth of an inch apart, and are not 

 very distinct. In the scale (fig. 13) the longitudinal stria? are from 

 a twenty-thousandth to a thirteen-thousandth of an inch apart, the 

 cross strife being a thirty-thousandth of an inch distant. 



Figs. 11, 12, 14 and 15, are from the upper side of the tip of the 

 upper wing ; in the scale (fig. 1 1) the longitudinal stria? are a twenty- 

 thousandth of an inch, and the cross stria? from a thirty-thousandth to 

 a twenty-five-thousandth of an inch apart ; both are very distinctly 

 brought out by a power of eight-hundred diameters. In fig. 12, the 

 longitudinal stria? are a fifteen-thousandth, and the cross stria? from 

 a thirty-five-thousandth to a thirty-thousandth of an inch apart. In 

 fig. 14, the longitudinal stria? are a ten-thousandth, and the cross striae 

 vary from a thirty-thousandth to a twenty-thousandth of an inch 

 distant. In fig. 15, which represents one of the characteristic scales, 

 the longitudinal stria? are from a ten-thousandth to a seven-thou- 

 sandth, and the cross stria? from a thirteen-thousand-five-hundredth 

 to a ten-thousandth of an inch apart. All these drawings were made 

 with the aid of the camera, the details being filled in on the stone by 

 the eye ; the scale of thousandths of an inch which accompanies 

 them was likewise set off by the camera. The measures are from 

 centre to centre of the markings. 



I now come to the consideration of the real nature of the markings 

 of the Amathusia Horsfieldii ; before doing so, however, I wish to 

 call attention to a paper by my friend Mr. Bowerbank, entitled ' On 

 the Structure of Scales on the Wings of Lepidopterous Insects. ' * 

 This gentleman, after minutely describing the methods adopted to 

 dissect out, and exhibit the structure of the scales, comes to the 

 conclusion that they consist of three distinct layers, viz., the upper 

 membrane, which contains the colouring matter; the striee, which 

 constitute the frame; and lastly, the under membrane, which is 

 nearly colourless ; and finally, that the stria? are in reality tubes. 



In Plate IX. is delineated one of the characteristic scales magni- 

 fied eight-hundred-and-twenty-five diameters. The outline of this 

 drawing was first made with a power of two-hundred-and-fifty 

 diameters, and by means of proportional squares enlarged to 

 the size corresponding to the magnifying power produced by the 

 twelfth; a scale of thousandths of an inch being set off with the 



* ' Entomological Magazine,' Vol. v. page 300. 



