316 MONOGRAPH OF THE GENUS SYNTHEMIS, 



The advantage of studying large series in a group subject to 

 considerable variation is self-evident. 



The publication of M. Rene Martin's magnificent "Cordulines, 

 Cataloge Systematique et Descriptif "* in 1906, has brought to 

 all odonatologists the means of studying this subfamily in detail, 

 and is of special value owing to the great rarity of a large number 

 of the species. Its appearance was the signal for renewed interest 

 in the group, and there followed in quick succession two excellent 

 papers on the scheme of classification of the subfamily. T refer 

 to Williamson's " Revision of the Classification of the Cordu- 

 liince"j and jSTeedham's " Critical Notes on the Classification of 

 the Corduliince."l AVilliamson's classification is a great advance 

 upon that adopted by de Selys and retained by Martin. Needham 

 suggests further improvements, bringing the comparative study 

 of the CorduliincB to a high degree of efficiency. 



All this excellent work contains no attempt at studying life- 

 histories or describing the earlier stages of the insects, that being 

 outside their avowed scope. The classification has been adopted 

 on the study of wing-venation only. Furthermore, the genus 

 Synthemis has throughout been neglected and left in its Selysian 

 state, owing no doubt to lack of material for the study of it. 



In the Williamson-Needham scheme of classification {loing- 

 venalion only), the subfamily Cordidiince, sens, lat., is divided 

 into two groups, which are themselves elevated to the rank of 

 subfamilies, viz.: — 



(1) MacromiincH, in which the anal loop of the hind-wing is a 

 compact set of cells, of Cordidegasterine form, i.e., slightly longer 

 than bi'oad, and the hind wing-triangle is never recessed to the 

 level of the arculus. 



(2) Corduliiiue, s.str., in which the anal loop (when present) is 

 very much elongated, and possesses a longitudinal bisector, and 

 the hind wing-triangle is often recessed to the level of the arculus. 



* Collections Zoologiques du Baron Edmond de Selys Longchanips, Fasc. 

 xvii., Brussels, 1906. 



tEntoDi. News, Vol.19, pp. 428-431, 190S. 

 JAmials Entom. Soc. America, Vol. i., No.4, Dec, 1908. 



