38 



As already stated, the insects of the genus Saturnla are among the 

 largest of the Nocturnal Lepidoptera, a few Hepialida and Erebi 

 alone equahng them m size. How far this circumstance gives them 

 the character of a typical group may be reasonably questioned ; to me 

 indeed it appears that an increased size in the species of any group is 

 in itself a proof of a certain degree of aberration : certainly if strength 

 of flight and compactness of form be considered, we must regard the 

 Lasiocampce and allies as much rather the real representatives of the 

 Linnsean Bombyces ; just as in the Butterflies, no one would consider 

 the species of Fapilio on account of their large size as the types, but 

 would confer that title on Vanessa and its allies, notwithstanding the 

 want of well-developed fore-legs. Another circumstance which might 

 be alleged as a proof of the typicality of the Saturnia, is the wide geo- 

 graphical range of the species, which occur in all quarters of the globe, 

 which peculiarity extends even to the minor divisions of the genus ; 

 thus we have very closely-alUed tailed species from North America, 

 India and South Africa ; I believe however that naturalists have at 

 length agreed in refusing to this circumstance the right of conferring 

 typicality on groups. 



Sattcrnia in fact appears to me to be one of those groups like Pa- 

 pilio among the Diurnal Lepidoptera, Carahus among the Carabidce, 

 Feronia among the Harpalidce, or Cicindela among the Cicinde- 

 lidce, which are of great extent and comprise a number of species, 

 generally of comparatively large size, which it is difficult to group 

 into well-defined sections or subgenera, although their forms are very 

 varied. One or more species may be detached and characterized as 

 distinct subgenera, but when the whole group is carefully studied, it 

 is ascertained that these particular species do not possess more im- 

 portant characters than the rest. I shall not attempt therefore, in 

 describing the African species alone of this group, to introduce a system 

 of distribution among the species, further than the artificial division 

 given below. 



The beautiful markings of the wings, and especially of the hind- 

 vnngs, of many of these insects, appear to indicate the character laid 

 down by Linnaeus and Fabricius, namely " Alse patulee," by which 

 we are to understand, that when the insect is at rest the fore-wings 

 do not closely cover the hind-ones, as is the case in the species with 

 dingy-coloured hind-wings, but leave their beautiful markings exposed 

 to view. Mr. E. Doubleday indeed informs me that the North 

 American S. Luna generally sits vrith its wings perpendicularly ele- 

 vated over its back, like a butterfly at rest. These beautiful eye-hke 

 markings of the wings are indeed a good character of the group, al- 

 though that which is aff'orded by the arrangement of the veins above de- 

 scribed is of higher importance. The latter indeed, together with the 

 emission of four branches from each joint of the flat pennated antennae, 

 may be considered as the essential characters of the genus, although 

 they have never hitherto been employed to distinguish it. Another 

 character, also hitherto unemployed, which will I think prove of im- 

 portance in determining the minor groups of Saturnia, consists of the 

 difference in the number of liranches iu the antennae of the different 

 species ; this I have carefully noticed in the following descriptions, as 



