266 



PHYSIOLOGY OF THE INVERTEBRATA, 



The author* has also examined the Malpighian tubules of 

 Libdhda dcj^ressa (Figs. 49 and 50), and has proved that they 

 have a renal function. 



Malpighu 



Fig. 49. — Malpighian Tubules of Libellula. 



Libdlula dqwcssa (the dragon-fly) is a voracious insect, which 

 lives in water, during its earlier stages, where it undergoes an 



imperfect metamorphosis, 

 the pupa finally creeping 

 out of the water, and chang- 

 ing into the imago. By ex- 

 perimenting with a large 

 number of the larval forms 

 of Libdlula, the author has 

 g extracted (from the larvie) 

 uric acid crystals, by using 

 similar methods to those 

 already described in this 

 chapter. 



Fig. 50.- 



-Malpighian Tuhules of 

 Libellula. 



A = Longitudinal section showing the va- 

 rious states of the epithelial lining. 

 B = Transverse section of tubule. X 230. 



In the imago or mature 



form of the dragon-fly the 

 Malpighian tubules number from sixty to seventy, and are 

 branched. Under the microscope, a Malpighian tubule is 



Proc. Boy. Soc. Edinh., vol. 15, p. 401. 



