32 



Transactions of the Society. 



Grabhamia dorsalis Mg. 

 Myzomia rossii Theo. 

 Mansonia uniformis Theo. 

 M. annulipes Mg. 

 Tccniorhynchus conopus Frau. 

 Nyssorhynchus jamesii Theo. 

 Sabcthes remipes Wied. 

 Desvoidia vcntralis Walk. 

 Mucidus altcrnans Westw. 

 Dinocerites cancer Theo. 

 Anopheles cinercus Theo. 

 A. maculipennis Mg. 

 JEdomyia squamipennis Ami). 

 Acartomyia longirostris Theo. 

 Verrallia butleri Theo. 

 Melanconion a trains Theo. 

 TJranotaznia pygmcca Theo. 

 Eretmapodites sp., undetermined. 



EXPLANATION OF TLATE III. 



1. Diagram of a hypothetical complete mouth in Diptera. This is seen from the 



dorsal side ; the maxilla? have been separated, and the mandibles removedf rom 

 their positions on the dorsal sides of the maxillae. The cardines and the sub- 

 mentum are supposed to have been dissected out of the enclosing membrane. 



2. Mouth-parts of Pulex irritant L. Viewed laterally. 



3. Diagram of a hypothetical labium of a common ancestor of the Tabanidse and the 



Muscidie. The labial palpi here are in the position they occupy in Dilophus, 

 and the palpigers are representative of those found in Chrysops excutiens L. ; 

 they are to be found in most of the Muscida? in a more posterior position, 

 reverting to the position of the part in Blatta. Seen as in fig. 1. 



4. Mouth parts of Gastrophilus equi F. In this family the trophi are quite rudimen- 



tary ; in the figure the parts have been cut from the head of a female, and are 

 seen from the ventral side. The upper part is the more anterior portion. 



5. Diagram of the mouth-parts of the female Culex pipiens L. The parts are seen 



from the dorsal side. On the labium is marked a depression where the " false 

 joint" is occasionally found. This rarely occurs in the females. 



6. Diagram of the usual type of mouth armature in the Empida; ; the trophi in the 



Syrphidse only differ by having a much greater development of the tracheae 

 on the paraglossae ; the characters of the mouth parts iu the Empida? are 

 variable, constant in the Syrphidaj. The diagram is seen from the dorsal side. 



7. The " false joint " in the labium of Dinocerites cancer Theo. Ventral view. 



Note. — The following letters are used throughout the plates :- 



m Mandible. 



I Laciuia. 



g Galea. 



mp Maxillary palpus. 



pf Palpifer. 



s Stipes. 



c Cardo. 



Maxilla. 



pr 



1 9 



lp 



PG 

 mn 

 8 m 

 Ir 



Paraglossa. 



Ligula. 



Labial palpus. 



Palpiger. 



Mentum. 



Submentum. 



Labrum. 



Labium. 



h Hypopharynx. 

 cl Clypeus, 



