304 STATES OF INSECTS, 



observed, when he put the skins of Libellula depressa into 

 water, that the colours common to both sexes were in 

 the substance of the skin, and remained fixed; while 

 those that were peculiar to one could be taken off with a 

 hair-pencil, and coloured the water: which therefore 

 were superficial, and, as it were, laid on a . The yellow 

 males, therefore, that Reaumur observed, were probably 

 such as had the superficial blue colour which distinguishes 

 them washed off! In Calepteryx Virgo Leach, the for- 

 mer are of a lovely silky blue, and the latter green. In 

 Agrions F. nature sports infinitely in the colours of the 

 sexes. 



In the order Hymenoptera there are often differences 

 equally great; the sexes of many of the Ichneumons and 

 Saw-flies are of quite different colours. The former tribe 

 Linne has divided into sections, from the white annul us 

 observable in the antennae of some, and from the colour 

 of their scutellum : but these are often merely sexual 

 characters b . The male of Anthophora retusa Latr., a 

 kind of wild bee, is wholly black, the female wholly gray, 

 and of so very different an aspect that they were long 

 regarded as distinct species ; a mistake which has likewise 

 occurred with regard to the sexes of Osmia ccerulescens, 

 another bee, of which the male has a bronzed and the 

 female a violet abdomen c . The nose of male Andrence 

 Latr. is often yellow, or white, as in A, litfemoi~rhoidalis — 

 when that of the female is black d . The labrum also is often 

 of a different colour in the sexes, as in Ceratina Latr. 



a Entomologische, &c. 224. 



b De Geer ii. 847. 850. Jarine Hymenopt. 100. 



c Kirby Mori. Ap. Angl. ii. 296. 264, 



d Ibid, ii, 142—. 144, 147, 148 3 &c, 



