duction by Meigen of the Stratyomidae and Syrphidas between 

 the families aUuded to, for the former appears to be nearly 

 allied to Beris (pi. 337), and the latter to the Conopsidae and 

 Muscidae, and my only reason for not attempting such an 

 arrangement in my Guide, was a desire to render references 

 to Meigen easy, and similar causes induced me to follow the 

 arrangement of Latreille through a great portion of the Hy- 

 menoptera. 



Mr. Haliday liaving detected a new species of Opetia in 

 Ireland, which he very kindly communicated to me, there are 

 now two found inhabiting our Islands. 



1. O. nigra Meig. v. 6. p. 357. tab. 66./. 17—20. 

 Length 1^ line, breadth 2f. 



Piceous black, antennae with the Srd joint ovate-conic, 

 shorter than the two basal joints united : eyes red : wings 

 fuscous, darker at the costa, and very pale at the opposite 

 margin : legs black. 



Mr. Haliday informs me that the males are common in Sep- 

 tember, and the females are rare in the vicinity of Holywood 

 in Downshire; Mr. Dale has also captured specimens in Au- 

 gust, at Lulworth in Dorsetshire. 



2. O. lonchopteroides Hal. — Curt. Brit. Ent. pi. 489. ? . 

 Mr. Haliday observes, that this species is distinguished by 



its longer antennae and the colour of the legs : it was taken 

 by him in the same neighbourhood as the last. 



The Plant is Ruscus aculeatus (Butcher's Broom). 



