440 Mr. WestwoocVs Descriptions of some new 



by means of heated glass, they exhibit signs of free electricity, 

 one of them being connected with the ground and the other 

 with the electroscope; but the general conclusion which he 

 attempts to deduce from the result of this single experiment 

 is certainly inaccurate, as it is founded on the assumption that 

 the colder wire will give always signs of positive electricity, 

 which we have seen is only true when the glass is thick and 

 at a certain temperature. The conditions however here stated 

 are not the only circumstances which influence the direction 

 of the electrical currents with heated glass, but as my expe- 

 riments do not lead to any definite result, I refrain from de- 

 scribing them. 



These currents may likewise be obtained by interposing 

 certain minerals between unequally heated wires ; thus mica 

 placed between platina wires and heated very strongly caused 

 a deflection in the galvanometer needle of 7°, and the mineral 

 called stilbite of 25° ; the current in both cases was from the 

 hot platina to the cold, 



Belfast, April 11,1837. 



LXXXIV. Descriptions o^ some new British Species of Hy- 



menopterous Insects, By J. O. Westwood, F,L,S, Sfc, * 



Encyrtus Dalmanni. 



CAPITE thoraceque laete aureo- vel coeruleo-viridibus sericeis, scutello 

 obscuriori; antennis thorace brevioribus sensim incrassatis, articulis 

 3 — 8, apice 9vi lOmiet 11 mi omnino albidis; alis anticis nigricantibus, costa 

 versus et pone medium obscuriori, basi, maculis duabus marginalibus op- 

 positis fasciaque subapicali albis ; abdomine chalybeio ; femoribus nigricanti- 

 bus; tibiis tarsisque anticis luteis, summo apice fusco, tibiis intermediis flavis 

 basi nigris, tibiis posticis nigris, tarsis pallide luteis. Species pulcherrima. 

 — Long, corp.f lin. Expans. alar. H lin^ 



Habitat in quercetis com. Oxon., Cantian. et Surrej. Tempore aestatis. 

 In mus. nostr. 



Encyrtus Zetterstedtii. 



Praecedenti valde affinis. Capite thoraceque laet^ viridi-coeruleis, sericeis ; 

 abdomine nigro-chalybeio ; antennis nigris, articulis 7 et 8 albidis, summo 

 apice fuscescenti ; alis anticis nigricantibus, sutura obscuriori, basi, macula 

 oblong-i ante medium alterisque 4 oppositis, 2, 2, marginalibus albis ; pedi- 

 bus nigris ; femoribus et tibiarum basi pedum anticorum nigris, tibiarum 

 apice tarsisque fulvis, tibiis intermediis et tarsis flavis illorum basi nigris, 

 tibiis posticis nigris summo apice luteo, tarsisque luteis. — Long. corp. ^ — | 

 lin. Expans. alar. 1 — H lin. 



Habitat cum praecedente. In mus. nostr. 



Encyrtus albipes. 

 Thorace viridi-a;neo tenuissim^ punctate ; capite viridi, fronte viridi- 

 aurea; antennis fere longitudine corporis, luteis, pilosis, filiformibus, scapo 

 albo-flavescenti ; scutello cupreo, laminis pieurarum violaceis, pedibus gra- 



* Coramunicated by the Author. 



