100 W. WESCHE OX SOME NEW SEXSE-ORGAXS IN DIPTERA. 



of the fore-coxae of Ocidromia glabricula, Fin. and on the 

 trochanters of the following Diptera : — 



JJibio pomonoe, F. 

 Dilophus febrilisj S ? • 

 Ilaematopota plurialis, L., ?. 

 H. crassicomis, Wklbg., ? . 

 Leptis scolopacea, L., $ . 

 Rhamphomyia pennata, Mg., ?. 

 Empis vitripennis, Mg., <£. 

 Dolichopus plumipes, Scop., c?. 

 Z). greiseipennis, Stan., <£ ? . 



Siccus ferrugineus, L., <^. 



Conops quadrifasciata, Seg., J. 



Lonchoptera Jlavicauda, Mg., $ . 



Pipuncukis campestris, Ltv., J 1 . 



Sp>ilogaster communis, Dsv., (? ? . 



Hidrotea dentipes, F., c£ ? • 



Parhydra coarctata, Fin., cf ? . 



Borborus equinus, Fin., c? 



Sphaerocera subsultans, F., ? . 



Limosina sylvatica, Mg., (^ $ . 



Phora incrassata, Mg., $ . 



Structure B I have seen on the maxillae and labial palpi 

 of Yespa vulgaris, on the first and second joints, and it will 

 be very often met with if it is looked for. It is also to 

 be found on many Diptera, particularly on the femora and 

 adjacent parts. Whether it has any connection or correlation 

 with Structure A I am unable to say, but as Structure B is 

 so often found without Structure A I should think not. 



These organs being found in so many different families, and 

 on species with such different habits, it is not possible to consider 

 them as specialisations, and no clue can be obtained as to their 

 use by the study of life-histories. Adopting the negative method 

 I arrive at the conclusion that : — (1) They cannot be organs of 

 sight or taste, taste hairs as we have seen being blunt and 

 generally hollow. (2) They are most unlikely to be tactile organs, 

 as their situation under the abdomen would render A useless^ 

 and B has no hairs or setae to convey an impression. (3) The 



