ANATOMY OF THE GOUT- FLY OF BAELEY. 



789 



support for liis tlieoiy, and his comparisons of certriin larval 

 types by whicli he ntteinpts to establish his view are adversely 

 criticised by Becker (1), 



Each mandible (w.) is a stout, lioavily chitinized liook with a 

 pointed claw-shaped anterior end and two posterior processes, 

 a smaller heavily chitiiiized dorsal one with a rounded posterior 

 surface Avhich articulates with the corresponding articular surface 

 of the intermediate sclerite, and a larger ventral one flattened 

 from side to side, into Avhich are inserted the depressor muscles 



Text-ficfure 3. 



•l,'S!CESjl-!3n' 





jrjC0ii^r; 



0-£ mm. ' 



C. taniopus. Dorso-Iateral view of coplialo-plinrj'iigcal sclerites, 



of the mandible. At the point of junction of the claw and the 

 anterior end of the ventral process there is a small, less heavily 

 chitinized, but sharply pointed, accessory tooth. The dorsal 

 process is broad from side to side and somewhat flattened dorso- 

 ventrally. It is held in close apposition to the articular surface 

 of the intermediate sclerite by the tension of the depressor and 

 levator mandibular muscles, and when these are cut, or even when 

 the larva is killed, the mandibles very easily come apart from the 



^ . Text-figure 4. 



Lateral view of ccplialo-pliaryngeal sclerites. 



intermediate sclerite. The two mandibles are fused togethei'^ 

 medianly over a small area but their articular surfaces .are 

 separate. 



The i-elations of the intermediate and pharyngeal sclerites can 

 best be understood by a reference to text-figs. 3 & 4 and text- 

 fig. 5, A-E, which represents a series of transverse sections 

 through the sclerites at the points marked by arrows on text- 

 fig. 3. As mentioned above, the intermediate and pharjmgeal 

 sclerites are fused. The form of the whole compound sclerite is- 



Proc. Zooii. Soc— 1923, No. LII. 52 



