498 Scientific Proceedings, Royal Dublin Society. 



Diseases, published by the Department of Agriculture and Technical Instruc- 

 tion for Ireland (51)^ in 1921. 



The work was continued at Coleraine during the spring and summer of 

 1921, and in the present paper it is proposed to give an account of the life- 

 history and habits of the beetle, together with detailed descriptions of the 

 morphology of the different immature stages, and general information 

 relating to the species in so far as it has been investigated up to the 

 present. 



The writer wishes here to acknowledge his indebtedness to Professor 

 G. H. Carpenter, of the Royal College of Science, under whose guidance the 

 work has been carried out, for much valuable help and criticism, especially 

 with reference to the descriptions of the different stages. 



2. — History and Synonymy of the Species. 



The nomenclature of the flax iiea-beetle has, unfortunately, been the 

 subject of much controversy, and many descriptions under many different 

 names have been published. Late workers, however, are agreed that the 

 correct name of the species is Longitars'us 2Mnndus — an agreement shared by 

 the present writer. 



From 1762, when Geoffrey (26) proposed for the flea-beetles the generic 

 name Altica, until 1807, when lUiger (37) divided his genus Ualtica 

 into nine sections, and defined the characters common to each section, 

 the position of the group was conjectural. Illiger gave to the seventh section 

 the name " Longitarses " ; and Latreille (46), in 1829, raised this section to 

 generic rank. Two years later Stephens (59), in a new system of classification, 

 founded the generic name 2'hyamis, and substituted it for Longitarsus Latr., 

 while a further change was made in 1834 by Chevrolat (16), who, instead of 

 employing either Longitarsus or Thyamis, used the new name Teinodadyla. 

 Longitarsus is, therefore, the legitimate generic name. 



The specific names parvulus and ater have been used simultaneously by 

 various authors. Patterson (48), to whom the first record of damage to flax 

 in Ireland by the species is due, uses the former, while several years later 

 Janson refers specimens from Irish flax fields to the same species (61). After 

 the publication of the catalogue of Gemminger and Harold (25), in which 

 ater is given priority (from Altica atra P.), many writers adopted the latter 

 specific name. Thus, it has been used by Bargagli (2) in Italy ; Fowler (24), 

 Sharp and Fowler (58), Hudson-Beare and Donisthorpe (36), and others in 

 England ; and Johnson and Halbert (39) and Carpenter (8) in Ireland. 



The numbers in brackets refer to the literature cited, 



