Explanation of Plate XVIII. 



Each Figttre is named on the Plate. 



Tarucus callinara, p. 278, iii)i)cr left-liand figure. 

 ,, venosus, p. 275, upper riglit-Iiand ligure. 

 ,, aUeratus, p. 280, lower left-haud iigure. 

 ,, theophrastus, p. 28(5, lower right-hand figure. 



Tlie ligurcs on j'late XVIIT of the virgae excitatae and tecforius 

 are iiiagnilied about 55 diameters. 



