BY T. G. SLOANE. 611 



coxae. Tarsi with penultimate joint narrow, simple. Type, 

 uE. iris Newm. Length 17-21 mm. 



Habits : on tree-trunks, under bark. 



This is a terminal genus of ancient origin, more allied to 

 Neohelluo than to any other genus. 



Enigma iris Newman. 



Ent. Mag., iii., 1836, 499; Castelnau, Trans. Roy. Soc. Vic- 

 toria, viii., 1868, 108; Gestro, Ann. Mus. Civ. Genova, vii., 

 1875, 874; Chaudoir, Rev. & Mag. Zool., 1872, 213. Variety 

 — jE . neivmani Castelnau, I.e., 108; Gestro, I.e., 872; jE . 

 splendens Castelnau, I.e., 109; Gestro, I.e., 873. 



Castelnau recognised three species of ^Enigma, ^ . iris, jE . 

 newmani, and J^J . splendens; but, Gestro, when reviewing the 

 Australian Helluonini, reduced these to two by uniting ^. 

 splendens to ^E. newmani. It is my belief, after examination of 

 thirteen specimens, four of which were females, that only one 

 species should be recognised, namely, jE. iris Newm.; and that 

 the narrower, more cordiform shape of the prothorax, on which 

 Castelnau and Gestro relied for the separation of ^E. neivmani, 

 should not be considered as of full specific value. The considera- 

 tions which induce me to come to this opinion are — (a) The form 

 with the narrow prothorax is reported by Castelnau from Sydney 

 (jE. newmani) and Port Denison (^. splendens) —that is, from 

 the southern and northern districts of the range of ^E. iris, 

 (b) A specimen (^) is in my collection (most likely from the Rock- 

 hampton District) which, by its unusually narrow prothorax, 

 with the sides more angustate to the base, and basal angles more 

 obtuse than in the typical form, evidently represents ^E. newmani; 

 but, I cannot think it more than a variety. (c)Mr. H W, Brown 

 has given me a specimen(^) which has the prothorax with the 

 sides more sinuate behind than usual, so that they meet the base 

 at right angles, the basal angles being marked and rectangular; 

 usually the sides of the prothorax are hardly subsinuate, and the 

 basal angles are obtuse at the summit My conclusion is that 

 the shape of the prothorax varies in jE. iris, and that the varietal 

 name jE. newmani{ = jE. splendens), may be used for the race 

 with the prothorax narrow. 



