40 Transactions of the Society. 



long hairs, but with no central sense-organs, such as are seen in the 

 second joint of Bibio and of most Nemocera (pi. VI. figs. 9-14). 



One interesting specialisation is found in Orthochilc nigroccrulu 

 Ltr., which has an elongated labium, a totally different arrangement 

 of the cardines, and a general similarity to the mouth-parts in the 

 Muscicke. This lengthening of the labium probably enables the 

 insect to reach the nectaries of flowers ; most of the other species 

 are raptorial, haunt marshy spots, and -feed on minute insects and 

 Gastropods (pi. VII. fig. 1). 



The mouth in the Phoridse has the cardines in the usual place, 

 and working the labrum and hypopharynx ; the latter part has in 

 some species a curious double point, which reaches well up to the 

 tip. Some species have a toothed labrum, which is a character of 

 the Dolichopidoe, and accentuates the affinity which these two 

 families have to each other. Though the tracheae on the paraglossa> 

 are of a different type from each other, it is remarkable that they 

 have also the short blunt hair in the cylinder at the extremity ; 

 this is a striking affinity, as I am not aware of this structure being 

 found in any other families in this situation. 



I have often seen these insects on plants and on window-panes, 

 but I have never seen them attack prey. Their appearance is 

 against them, but I have no evidence that thev are of raptorial 

 habits (pi. VII. fig. 2). 



Group 5. — As I have dealt with the first section of this group 

 in previous papers,* I shall confine myself to giving a list of species 

 in which I have found the characteristic rudimentary palpus : — 



Myioccra carinifrons Fin. 



Graphomyia metadata Scop. 



Mesembrina mcridiana L. 



Musca domestica L. 



M. corvina F. 



Cyrtoncura stabidans Fin. 



* ' Undeseribtd Palpi in Diptera,' Jour. Roy. Micr. Soc. 1902 ; ' The Labial and 

 Maxillary Palpi in Diptera,' Trans. Linn. Soc. London, Zool., ser. 2, vol. ix. 



EXPLANATION OF PLATE ATI. 



1. Tropin of OrthocMle nigrcecerula Ltr. Lateral view. 



2. „ of undetermined species of Phora. Dorsal view. 



3. „ of Ha matdbia irritans L. 



4. Teeth on the labium of //. irritans. 



5. „ of Aorellia ttriolata Mg. (Cordyluridse). 



6. Tropin of Ccelopa .frigid a Mg. (Phycodromida)). Dorsal view 



7. „ of Helomyza rufa I In. Dorsal viev*. 



8. Labial palpus ot Stiomyza cinerella Fin. 



9. Maxilla of £>. cinerella. 



10. Tracheae of Sapromyza prsew ta Fin. Dorsal view. 



11. „ of 8. pneufta. Viewed ventrally. 



12. Maxilla of S. praeueta. 



