293 



are without traces of discal costae. As the abdomen is missing 

 the sex of the type is doubtful. 



Dohrnia boisduvali, Blackb. (formerly Ananca). 



Silis australis, Blackb. 

 Var. D. simplex, Champ. 



This species has been rather unfortunate in its synonymy ; 

 in 1891 it was described as Silis australis, of the Mala- 

 codermidae; in 1893 it was transferred to the genus 

 Ananca,^) of the Oedemeridae ; but australis being already 

 in use in that genus, the specific name was altered to 

 boisduvali. Still later (1899) it was found to be congeneric 

 with a species (D. simplex) referred by Champion to Dohrnia, 

 .and the generic determination was accepted by Blackburn. 



There are before me a co-type of boisduvali, a South Aus- 

 tralian specimen labelled by Blackburn as boisduvali, and 

 •several other South Australian and Victorian specimens that 

 agree with them ; and numerous Tasmanian specimens (in- 

 -cluding several pairs taken in cop.) of simplex, and I can 

 only regard simplex as a Tasmanian colour-variety of 

 boisduvali. In the original description of the latter the pro- 

 thorax was noted as having "lateribus subtus appendiculatis" ; 

 and again, "The downward-directed appendage of the sides 

 of the prothorax is no doubt characteristic of the male." But 

 there is no true appendix ; near the base of the prothorax 

 there is an impressed line, behind which an elevated line 

 margins the base, and this, when curving downwards on each 

 side, gives an appearance as of an appendix ; it is slightly 

 more pronounced on boisduvali than on simplex, but is not 

 sexually variable. In comparing the two forms, Blackburn 

 stated that boisduvali differed from simplex "by the colouring 

 of its head and legs,( 47 ) and by its much smaller prothorax, 

 the sides of which are much more strongly curved behind the 

 .anterior tuberosity, making the segment very much narrower 

 in the hinder part and the extremities of the base much more 

 prominent." But he evidently compared a male of one form 

 with a female < 48 ) of the other, as the male of each form differs 



(46; Considered by Champion as a probable synonym of 

 ! Copidita. 



(47) On most specimens the head has a more or less brassy 

 gloss, occasionally with a faint bluish tone ; but on boisduvali the 

 front parte become testaceous, and on simplex plain black ; on 

 the former, also, the front tibiae are almost wholly pale, whilst 

 on the latter they are obscurely pale only at the base ; but colour 

 variations such as these are frequent between Tasmanian and 

 mainland specimens of many insects. 



(48) The sexes may be 'readily distinguished by the tip of the 

 .abdomen. 



