Systematic Position of the Oenns Mycetobia, Mg. 1 Hi 



Turning to tlie llllYPIIID.E, we fiml that in Olbiogaster 

 (fig. 2 b) the hxhiuni (lifters from that of Mi/ce(ohia cliietlv in 

 liaving the nientuin completely fused on to the guiar plate, 

 while the former, instead of the latter, provides the attacli- 

 ment fur the maxillary stij)ites. lihyphus (fig. 2 a) presents 

 a very different structure : there is a well-marked median 

 organ situated between the labolla, which is re^%'irdcd by 

 Kellogg (* Psj'che,' vol. viii. p. 35(5) as representing tho 

 fused glossa3 ; a small luirrow plate is inserted between the 

 nicntum and the gular plate, on each side of which last is 

 another plate, which may, j)erhaps, bo regarded as the cardo 

 of the maxilla. 



A gular plate entirely comparable with that of the 

 RHYnriD.^ occurs in Ptychoptera and in Trichocera, though 

 it appears to be absent in Di.va. A similar plate is to be 

 found in at least some of the BuACilYCERA and in the 

 MusciD.E, where it is fused with the head-skeleton ; it has 

 been figured for ^[usca by Wesche (J. R. Micr. Soc. 1909, 

 pi. iv.), who regards it as the raentum. 



Venation. 



The Rhyphid.e and MycetophiltD/E agree in having a 

 costa which docs not extend beyond the tip of the wing, but 



^"' Cu;, An 



"Wing of (a) Mycetohia i^allipes, Mg., (h) Olbiogaster sackeni, Edw. 



differ widely in that the former have a three-branched media 

 and a discal cell, whereas the latter never have more t;lian a 

 two-branched media and no discal cell. 



At first sight it is not easy to connect these two types, but 

 if in the wing of N/n/pIius we suppress the third branch of 

 the media, and with it the cross-vein forming the discal cell, 

 a condition very much resembling that of Mycetobia is arrived 



Ann. tC- Mag. N. Hist. Ser. 8. Vol xvii. 8 



