136 DB. J. B. HlCKS ON A NEW OBGAN IN INSECTS. 



Subfam. Gteomtzides, Fallen. 

 Gen. G-yhnopa, Fallen. 



169. G-TMNOPA ? GUTTICOSTA, n. s., fcem. Nigra nitens, pectoris lateribus 

 canis, thoracis fascia abdominisque basi pallide flavis, tibiis tarsisque ferru- 

 gineis, alis subflavescentibus gutta costali nigra. 



Female. Black, shining. Head wanting. Thorax with a pale yellow band. 

 Pectus hoary on each side. Abdomen blackish, cupreous towards the 

 base, which is pale yellow. Tibise and tarsi ferruginous. Wings slightly 

 yellowish, with a black dot on the costa before half the length ; veins yel- 

 lowish. Length of the body 1^ line ; of the wings 3 lines. 



170. Gymnopa IKFTJSA ?, n. s., mas. Nigra, thorace subpubescente, scutello 

 longi-obconico, abdomine seneo-nigro, pedibus halteribusque testaceis, alis 

 limpidis venis nigris. 



Male. Black. Head wanting. Thorax slightly pubescent. Scutellum long- 

 obconic. Abdomen seneous-black, shining. Legs and halteres testaceous. 

 Wings limpid ; veins black ; discal transverse vein parted by more than 

 its length from the border, and by less than twice its length from the 

 prsebrachial transverse vein. Length of the body 1£ line ; of the wings 

 2£ lines. 



On a New Organ in Insects. By John Bbaxton Hicks, Esq., 

 M.D. Lond., E.L.S. Ac. 



[Read June 17, 1856.] 



About a month since my attention was directed towards a pecu- 

 liar structure in the halteres of the Mhingia rostrata, by Mr. 

 Purkiss, who is an energetic and zealous searcher for microscopical 

 objects, and who, from the position and structure of this organ, 

 considered it to be the organ of smell. How far this is probable, 

 I will leave the Society to judge at the termination of this paper. 

 I instantly directed my attention to the subject, and I will en- 

 deavour to lay before the Society the results at which I have 

 arrived up to the present time, apologizing for the incompleteness 

 of the investigation, in consequence of my anxiety to bring it 

 before the Society previous to the summer recess. 



If we dissect a perfect fly, there will be seen in the centre of 

 the thorax the great thoracic ganglion, which is formed by the 

 fusion of the three thoracic ganglia into one. From thence it 

 will be plainly seen that the first branch passes to the anterior 

 leg ; the second (much larger) enters the base of the wing after 

 giving off a few branches to the muscles ; the third branch passes 



