32 DIPTERA OF AUSTRALIA, 



lettei'press. From this we shall be able afterwards without much 

 difficulty, to interpret correctly any incomplete venation, which, as 

 he intimates, is often by far more difficult of correct understanding 

 than a very intricate example. 



Veins.* 



Primarily we have six longitudinal veins issuing from the two 

 main trunks, three from the tirst and three from the second ; all 

 the remaining venation springs from them. 



a. Transverse shoulder-vein (vena transversa humeralis). 



b. Auxiliary vein (vena auxiliaris). 



c. First longitudinal vein (vena longitvdinalis prima). 



d. Second longitudinal vein (vena longitudinalis secicnda). 



e. Thii'd longitudinal vein [vena longitudinalis tertia). 



f. Fourth longitudinal vein (vena longitvdinalis quarto). 



g. Fifth longitudinal vein (vena longitudinalis quinta). 

 h. Sixth longitudinal vein {vena longitudinalis sexto). 



i. Small or middle transverse vein {vena transversa minor s. 

 media). 



k. Hinder transverse vein {vena transversa posterior). 



I. ' 



m. 



n. 



0. 



p>. Anterior Ijasal transverse vein (vena transversa basalis ante- 

 rior). 



q. Posterior basal transverse vein {vena transversa basalis poste- 

 rior). 



r. Rudiment of a fourth trunk. 



s. Axillary incision {incisura axillaris). 



t. Anterior bi-anch of the third longitudinal vein {ve7iai longitu- 

 dinalis tertioi ramus anterior). 



u. Anterior intercalary vein {vena intercalaris anterior). 



V. Posterior intercalary vein {vena intercalaris j>osterior). 



* Letters under this and the next head refer to diagram on Plate ni., 

 fig. 25. 



'Costal vein (vena costalis). 



