Insects. 



7917 



be compared with those of the diurnal Lepidoptera. The most remarkable species in 

 this respect appertains to the subgenus of the Bombyces, those called "Ecailles." 

 The genera Noctua and Sphinx have scales less brilliant, but perhaps from their soft 

 and quiet colouring they are more beautiful. The upper surfaces of the wings of some 

 of the exotic diurnal Lepidoptera exhibit portions of more or less size of a beautiful 

 blue or brilliant green. These bright colours, the microscope shows, are due to a par- 

 ticular and special formation of the scales. The intervals between the striae are pretty 

 regularly transversely divided into longish squares. Each of these squares has 

 a small circular cavity diminishing and rounded to the bottom, like the interior of a 

 common mortar. The scales from the butterfly Ulysses, which is a beautiful blue, and 

 those from Paris, a brilliant green, show these markings. It should be remarked 

 here that the upper surface of scales of this description are more brilliant than the 

 surface next to the membrane of the wing, just contrary to almost all other scales, as 

 has been already shown. It should be observed that the colours of these beautiful 

 scales are somewhat dull upon the butterfly, and have only all their brilliancy when 

 seen under the microscope. Another property of some scales is that when they are 

 examined by transmitted light they produce the brilliant reflections of precious stones. 

 Numerous observations show that almost all scales, even those which are opaque, 

 decompose light more or less when observed with the flame of a candle or a lamp. 

 The scales which best produce this effect are somewhat rare. They are sometimes 

 found in the diurnal butterflies upon the white part of the wing, especially when 

 tinged with the blue or violet, such as are found in certain of the exotic Nymphalidae. 

 Among the numerous species of this genus I would cite the Bolina Alcithous and 

 Lasinassa. Some of the nocturnal Lepidoptera have scales producing these brilliant 

 colours. The most remarkable come from the genus Noctua. They are those which 

 form the pearly or golden bands which are seen below their first wings on the inner 

 margin, starting from the base. The inner margin of the top of the lower wing, and 

 which is equally pearly or golden, has also very beautiful scales. The Noctua 

 P. Gamma, or M. glyphica, are some of the best for this kind of observation. My 

 investigations on the decomposition of the rays of light by the scales of Lepidoptera, 

 have shown me that a portion of those which possess this property most effectually, 

 whether opaque or transparent, have very fine and indistinct cylindrical striae, covered 

 by very crowded granulations. These granulations appear to add much to the 

 beauty of the reflections, which are always more vivid than in scales without gra- 

 nulations, whatever may be the simplicity or transparency of the striae. When the 

 granulations are only semi-transparent, the reflections of the scales, which vary 

 according to the direction of the light, are always very brilliant ; if, on the contrary, 

 they are only slightly opaque, these reflections are darker, but richer in colour. Some 

 splendid examples of this kind are found in scales which have only the appearance of 

 slight granulations and no striae, such as those of the Nymphalidae, Bolina, Alcithous 

 and Lasinassa, of which I have already spoken. It seems to result from these different 

 observations that the most brilliant reflections produced by the scales of Lepidoptera 

 are due rather to the arrangement of their lamellae than to the regularity and trans- 

 parency of their striae. — Bernard Deschamps, in the ' Annales des Sciences Naturelles,' 

 translated and communicated by A. G. Latham, Manchester, February 17, 1862. 



Lasiocampa Rubi bred in January. — Captain Russell states that he kept a larva 

 of Lasiocampa Rubi in his study, which has a constant fire in it, and is very warm 

 with a southern aspect, since October 8th, 1861 . On November 27th it turned to pupa. 



