140 ' THE entomologist's recoru. 



structure ? I see no reason why this structure should be confined to 

 the " white" scales, for they, with pigment, would be very good coloured 

 scales. This would account for two kinds of colour, pigmentary and 

 structural, and seems to me to offer the most reasonable explanation of 

 the difficulty. I do not profess to be up to the times ; I do not know what 

 others have i)ublished on the matter (except Mr. Tutt) ; I know I may 

 be very wrong, and perhaps even in a great muddle, but this appears 

 to comprise tlie gist of the question as far as I understand it. — (Rkv.) 

 C. R. N. Burrows, Rainham, Essex. January I5th, 1895. 



I should like to mention a fact which I have noticed respecting the 

 brilliant metallic colour of certain exotic Lepidoptera, such as the 

 JJraniae — vulgaris, sloanus, rhij^haeux. &c. — with a view to eliciting 

 from others more capable than myself their opinions as to the shape of 

 the scale being an imjiortant factor in connection with these glistening 

 metallic wings. This is to the effect that these scales are not fiat, but 

 concave, and the more brilliantly metallic the more concave are they. 

 This is markedly' the case in that most gorgeous of all insects, Urania 

 rhipliaeus. Those who have never seen the wings of this moth under 

 the microscope have a new and delightful sensation in store for them, 

 for words fail in describing the glories of it. Parts of the wing resemble 

 bands of molten gold, and there are a few scales near the hind margin 

 of the lower wing, which glow with the brightness of the coloured 

 fires of the pyrotechnist. Some years ago I called the attention of the 

 late Mr. Philip Henry Gosse, who had then in preparation a work on 

 the Uranirlae — of wliich, by the way, I have not heard since his 

 decease, which occurred shortly after our correspondence — to the pro- 

 nounced concavity of these scales, and received a reply that the 

 observation was of scientific importance, and might result in some 

 useful knowledge regarding the colours of insect scales. It is notice- 

 able that altliough tlie beautiful bhie-green spot of Papilio hnddha is 

 not metallic to the naked eye, under the microscope, with good light 

 from the condenser, the scales are vividly so, and sparkle with the 

 lustre of gems. The British Lepidoptera afford but few examples of 

 metallic scales, these being confined pretty much to Miselia oxyacanthae 

 Amphipyra pyramidea, and tlie Plnsiae. The shining brass of Phisia 

 chrysitis is very disappointing under the microscoi)e [vide, British Noctiue, 

 ii., p. xvi. Ed.] ; the scales ai'e flat, have a kind of transparent appear- 

 ance, and are of little beauty. — Joseph Anderson, junr., Chichester. 

 February fjth, 1895. 



The extraordinary appearance of the " green " scales of Thecla rnhi 

 when viewed by reflected light under a low power of the microscope 

 induced me to investigate tliem further, with the result that I found 

 the same appearances that Dr. Riding has described (Ent. Record, vol. vi., 

 p. 8B). By delicate focussing, it became evident that the curious 

 tortoiseshell-like patches were within the substance of the scale and 

 beneath the riljs. These patclies certainly seemed to correspond with 

 the broken-u]( corruscations of green colour which one sees by reflected 

 light. Under the microscojje, the gi'een scales of Miselia oxyacanthae 

 do not resemble those of T. rnhi, the green appearance in the former 

 reminding one of the manner in wliich the blue scales of the Lycacnidae 

 produce tlieir colour, both alike being colourless when viewed by 

 direct transmitted liglit. — R. M. Pkideaux, New^jort, Isle of Wight. 

 Feb. 2Uh, 1895. 



