210 PROCEEDINGS OF SOCIETIES. 



The number who attended the first excursion was twenty-four, and the 

 second, fourteen. 



And now, gentlemen, trusting that the vacation will not be spent 

 by any of us in idleness, but in field or open-air studies, let us adjourn 

 until October next. 



A. H. Haliday, A.M., communicated a note supplementary to the list 

 of the genera Diptera the earlier stages of which are known (see " Pro- 

 ceedings," p. 180 of this volume). 



At the time this list was drawn up I had not seen a paper by Pro- 

 fessor Eondani ("Osservazionisopraparecchie specie di esapode afidieidi 

 etc." nei Nuovi Anali delle Scienze Naturali de Bologna, A. D. 1847), 

 in which two more genera of the Syrphidae are illustrated by the follow- 

 ing examples : — 



Pipiza varians Edn. 



Paragus bicolor Ltr. P. quadrifasciatus Mg. P. coaduna- 

 tus Rdn. 



In the same paper Eondani has given the history also of another 

 Cecidomyia, the larva of which feeds on Aphides, and of Leucopis ltj- 

 soria, and of four other (new) species of that genus. 



In the " Transactions of the Zoological and Botanical Association of 

 Vienna," vol. v., A.D. 1855, Frauenfeld has traced the history of some 

 species of Diptera, here enumerated according to the determination by 

 Schiner in, the sixth volume of the same " Transactions," A.D. 1856 : — 



Cecidomyia (Asphondyla) scrophttlaria Sch. Asph. sarothamni 

 Lw. 



Tephritis mamttljE Fr. (T. terminata Mg. not Fin.) T. femo- 



ralis Desv. (Aciura). T. longirostris Lw. 



AGROMYZA MAURA Mg. 



GEOLOGICAL SOCIETY OF DUBLIN. 

 WEDNESDAY EVENING, MAY 13, 1857. 

 Professor Apjohn, M.D., F.E. S., M.E.I. A., in the Chair. 

 Eev. Professor Haughton read the following paper — 



ON THE SILICEO-FELSPATHIC ROCKS OF THE SOUTH OF IRELAND. 



It is well known that siliceo-felspathic trap rocks of a peculiar kind are 

 found in the mining district of the Ovoca, county of Wicklow, and in the 

 mining district of Bonmahon, in the south of the county of Waterford ; 

 and the recent investigations of the Geological Survey in the west of 

 Kerry and Cork have brought to light the existence of great quantities 

 of similar rocks in the neighbourhood of Killarncy, and in the moun- 



