The Zoologist — January, 18438. 1043 



account of the parallelism of their variation; that is to say, each 

 exhibits similar variations, while each has also one or more variations 

 peculiar to itself. A brief sketch of the bibliography of these insects, 

 which are almost ubiquitous, may possess some interest. 



In 1776 the Vienna Catalogue gives but one species which can be 

 regarded with any certainty as belonging to the group : this is called 

 Russata. 



In 1792 Fabricius, in his 'Entomologia Systematica,' also gives 

 one only, which is called Centum-notata. 



In 1803 Haworth combines these under the name Centum-notata, 

 but describes four varieties called a, 8, y and 3"; he also adds four 

 other species, which he calls Immanata, of which he describes four 

 varieties, a, &, y and £; Marmorata, of which he describes three varieties, 

 n, & and y ; Perfuscata, of which he describes three varieties, a, and y ; 

 and finally Comma-notata, of which he says " Nunquam variat." 



Tn 1829 Mr. Stephens adds three species, Concinnata, Amaenata and 

 Saturata, and Mr. Curtis adds a fourth, Boreata. 



In 1850 Mr. Doubleday, for the first time, divides this formidable 

 array of names into two species : 



Russata including Immanata including 



Russata \ Immanata 



Centum-notata } aS ^onymom. Marmorata, as a var. 



Comma-notata, as a var. Amaenata, as a var. 



Perfuscata, as a var. 

 Saturata, as a var. 

 Boreata, as a var. 



It will be observed that Mr. Doubleday omits Concinnata of Stephens, 

 to which allusion has been made above. 



Tn 1847 Herrich-Schaeffer combines these eight described species 

 with four others, Passeraria, Slrigulata, Truncata and Variata, under 

 the original name of Russata, without expressing a doubt as to their 

 constituting but a single species. 



In 1857 Guenee endorses this view, giving a long aud learned 

 dissertation on the subject; and finally, 



In 1862 Mr. Doubleday, in a second edition of his ' Synonymic 

 List,' again separates them, as before, into Russata aud Immauata, and 

 every entomologist in England now follows this master mind aud 

 guiding spirit. 



