MR. R. SHELFORD ON A NEW GENUS OE DIPTERA. 153 



habits. Brues in his latest monograph on the Phoridse [9] does not include 

 Ihaumatoxena, but it is possible that he did not receive Silvestri's paper in 

 time to draw his attention to the fact that the position of Thaumatoxena in 

 the order Rhynchota was a very precarious one. Wasmann [4] has described 

 some other termitophilous genera_, Termito.venia and Termitomyia, which he 

 would include in yet another family, the Termitoxenidee ; they appear to 

 have some features in common with Thaumatoxena ; Brues includes them in 

 the Phoridaa. Their development is very remarkable, since they undergo no 

 metamorphosis, and Termitomyia is also viviparous. 



Except in the shape of the head, which resembles the head of Chonocepliahis, 

 and in the form of the antennae, which is characteristically Phorid in appear- 

 ance, u:^nigmatistes is very unlike all the foregoing genera. Thaumatoxena 

 is a form apart, the most outlying member of all. The " Puliciphoridse "" are 

 characterized by the small thorax, swollen abdomen with thin cuticle and 

 isolated scutes, and the long legs. Moreover, in all the genera enumerated 

 above, the rostrum is prominent and is composed of easily recognizable and 

 separate elements. In ^Enigmatias the rostrum has not been properly demon^ 

 strated, but if it exists it is certainly minute and rudimentary. Both in 

 urEnigmatias and ^nigmatistes the head fits closely to the thorax, and in the 

 latter genus, at any rate, it is incapable of much movement owing to its pro- 

 jection above the level of the pronotum ; the labrum is deflexed and covers the 

 entry to the mouth quite completely. In an attempt to raise the labrum of my 

 specimen and examine the mouth-parts in situ, the head broke away from 

 the thorax so that the position of the trophi was considerably disturbed. 

 I am, however, confident that no portion of the mouth-parts was lost, and so 

 can affirm with certitude that the proboscis or rostrum of yEnigmatistes is 

 represented by a minute membranous hypopharynx which is quite invisible 

 until the labrum, covering it, is removed. This reduction of the mouth-parts 

 alone is sufficientito xevaoYQ yEnigmatistes and yEnigmatias from the neighbour- 

 hood of the other aberrant genera of Phoridge described above. It is difficult 

 to see how the insect can feed, since it is provided merely with a pair of 

 maxillary palpi and a rudimentary hypopharynx, and the same may be said 

 of yEnigmatias hlattoides. yE. hlattoides was found in company with ants, 

 and it has been suggested to me that it is fed by the ants thrusting their 

 jaws into the mouth of their guest and regurgitating some liquid nourishment 

 from their crops, very much as the Staphylinid beetle Atemeles marginata, 

 Gravenh., is fed by ants. The suggestion was sufficiently ingenious to lead 

 me to examine the mouth-parts of the Staphylinid in question, in the hopes 

 of discovering at least some reduction thereof to lend support to this view, 

 but I was doomed to disappointment, for the mouth-parts in this species 

 are perfectly well-formed. Moreover, I cannot find an instance of the re- 

 duction of mouth-parts in any other myrmecophilous or termitophilous insects ; 

 and the fact that ^Enigmatias Schioarzii was not taken in the company of 



