316 THE DESCRIPTION rtF SPECIES. 



not, I fear, be coincided with by many of our Lepidopterists. 

 On the South Downs of Sussex and Kent, Agestis assumes 

 what may be called its typical form. I have taken it at Rams- 

 gate, Dovor, Hythe, Hastings, Rye, Brighton, Worthing, 

 Little Hampton, Chichester, Portsmouth, Isle of Wight, 

 Dorsetshire, Somersetshire ; and throughout this range it is 

 very similar : then, going upwards, I have met with it at 

 Worcester, Birmingham, Shrewsbury ; and here an evident 

 change has taken place, the band of rust-coloured spots 

 has become less bright ; at Manchester these spots have 

 left the upper wing almost entirely ; at Castle Eden Dean 

 they are scarcely to be traced, and a black spot in the centre 

 of the upper wing becomes fringed with white, in some speci- 

 mens it is quite white; the butterfly then changes its name to 

 Salmacis. We proceed further northwards, and the black pupil 

 leaves the eyes on the under side, until at Edinburgh they are 

 quite gone ; then it is called Artaxerxes. The conclusion I 

 arrive at is this, that Agestis, Salmacis, and Artaxerxes, are 

 but one species. 



Art. XLIX. — On the Description of Species. By the Rev. 

 G. T. Rudd, M. A. 



Much discouragement often impedes the first steps of the 

 young and ardent collector, from the difficulty he experiences 

 in satisfactorily determining the name of an insect he may 

 capture or possess, in consequence of the vague manner in 

 which the description of it is, too often, drawn up: a from the 

 same cause, great and constant perplexity in nomenclature 

 embarrasses the more advanced and practised entomologist. 

 Whoever sits down to investigate and " make out " individuals 

 of a genus in which the described species are numerous, will 

 soon discover the unsatisfactory progress he can attain, the 

 uncertainty in which he remains, after the most careful study 

 of his author as to the specific types to which his several 

 specimens are to be referred. b And whenever any particular 

 group becomes the subject of a monograph, we find the writer 



a Kirby's Monog. Apum Anglise. Gyllenhal's Insecta Suecica must be ex- 

 cepted. 



b The Genera Harpalus— Amara - Cercyon— Aleochara, &c, of "The Illus- 

 trations," for examples. 



