MAXILLA EY PALPI IN DIPTEEA. 



227 



and consequently less archaic, than OpTiijra leucostoma (PL 9. fig. 17), which has an 

 ahnornially short lahium, the maxillary palpi well marked, and the parts on the labella 

 very evident. 



II. Fiibescent Eyes. — All the flies in the Cyclorrhapha with pubescent eyes that I 

 have examined, either have the maxillary palpi only, or possess rudiments of them, 

 e. g., Syrphidae, Polletes, Syetodesla, Hydrotea occulta. Some species of Phoridae 

 are apparently an exception; it is, however, very doubtful whether this family is in its 

 proper division. 



III. Venation of Wings (text-figs. 3 & 4). — The rudimentary palpi seem to follow the 

 venation of the wings in a curious manner. The cell formed by the 3rd and 4th 

 longitudinal veins (subapical or 1st posterior cell) is open in the Anthomyiidfe, begins to 

 close in Cyrtoneura stahulans, is nearly closed in Musca domestica, and is quite closed 

 in Phito melanocephala. The palpi gradually diminish through these species till no sign 

 is left in P. melanocephala. 



Fis. 3. 



Kr. 4. 



^K^i«iACft«<^-'^"2S" 



Wing of Polietes lardaria. 



Wing of P}iito melanocftphala. 



IV. Tegulce. — The tegulte also seem correlated : — 



(1) When all the palpi are well developed, as in Splicerocera sithsultans, the snbapical 



cell of the wing is open, the tegulae are absent. 



(2) When the palpi are more or less rudimentary, as in the Anthomyiidse, the cell 



still remains open, but the tegulae are well marked. 



(3) When the palpi are rudimentary, as in Cyrtoiieura stahulans, the cell begins to 



close and the tegiilaj increase in size. 



(4) When the palpi are very rudimentary, as in ITusca domestica, the cell is still more 



closed, the tegulae remain large. 



(5) When no trace of the palpi can be seen, as in CalUphora, the cell is still more 



closed, the tegulse remain large. 



(6) In Fhito and Melanophora the tegulee are still more developed, no trace of palpi 



can be seen ; the 4th longitudinal or median vein has closed the 1st posterior cell 

 so much that it has left the margin. 



(7) In (Estrus the mouth-parts are rudimentary, the venation has left the lower part 



of the wing, and the tegulae are at their largest development. 

 AA^orking on the above data, a fly may be imagined with hairy eyes, a plumose arista, 

 a venation approximating to that in the Anthomyiidae, mandibles fused into the labium, 

 which would be short and stout ; maxillaj also absorbed, but with both palpi well 



SECOND SEKIES. — ZOOLOGY, VOL. IX. 31 



