EXPLANATION OF THE PLATES OF DETAILS. 



PLATE I. 



Fig. I. Anterior Wing of Papilio Hornerus. 



a, Costal nervure. 



b, Subcostal nervure. 



b 1., b 2., b 3., b 4., b 5., Subcostal nervules. These, as well as the discoidal and median nervules, bear 



numbers corresponding to the ordinal numeration used in the text. 

 c 1., c 2., Discoidal nervules, the second appearing to be a fourth median nervule : the nervure itself 



wanting. 

 </, Median nervure. 

 d 1., d2., dZ., Its nervules. 

 e, Submedian nervure. 



f, Internal nervure. This nervure is wanting in many of the Diurnal Lepidoptera. 

 <7 I., Upper disco-cellular nervule. 



g 2., Middle disco-cellular nervule. 



g 3., Lower disco-cellular nervule. The very oblique position of this nervule causes the second discoidal to 



appear to be a fourth median nervule. 

 h, Intemo-median nervule. This nervule is rarely found, except in the Papilionidae and Morphidse. 



II. Posterior Wing of Papilio Hornerus. 



a, Precostal nervure; bifid, its lower branch united at its termination to the costal. It is this nervure which 

 in a great proportion of the Heterocerous Lepidoptera projects beyond the margin of the wing, in the form of 

 a single stout bristle in the males, of several weaker ones in the females, which are received into a more or 

 less distinct one on the under side of the anterior wing. This structure never exists in the Diurnal or 

 Rhopalocerous Lepidoptera, although, for nearly seventy years, most British writers on the Lepidoptera 

 have persisted in stating its existence in the male of Apatura Iris. 



a, b, b\., b 2., as in Fig. I. 



e, Discoidal nervure, simple in the posterior wings. 



d, d 1., 1*2., rf3., e,f, as in Fig. I. 



g 1., <7 2., Upper and lower disco-cellular nervules. As in the posterior wings the discoidal nervure is always 

 simple, there can never be more than two disco- cellular nervules. One or both are very commonly wanting. 



Fig. III. Anterior Wing of Morpho Perseus. All the letters and figures as above. The disco-cellular nervules will be at 

 once seen to be in a very different position to those of Fig. I. 



IV. Posterior Wing of Morpho Perseus. All the letters and figures as above. Precostal nervure simple. Discoidal 

 nervure united to the second subcostal nervule, and appearing to be a third subcostal nervule. Upper 

 disco-cellular nervule consequently wanting. Lower disco-cellular nervule wanting. Cell consequently 

 open. 



Fig. V. Anterior Wing of Gonepteryx Leachiana. Letters and figures as above. Subcostal nervure with only four nervules. 

 Upper disco-cellular wanting. The first discoidal nervule united at its origin to the subcostal nervure. 

 Internal nervure very slender, running into the submedian. Interno-median nervule wanting. 

 VI. Posterior Wing of Gonepteryx Leachiana. All the letters and figures as above. Precostal simple. 



FlG. VII. Anterior Wing of Mechanitis Lysidice. Letters and figures as above. Lower disco-cellular nervule bent at an 

 acute angle. 



g, Rudiment of the discoidal nervure, its basal portion being atrophied. 



VIII. Posterior Wing of Mechanitis Lysidice. Letters and figures as above. Precostal nervure simple. Costal nervure 

 united for nearly half its length to the subcostal. This structure occurs only in the female. Upper 

 disco-cellular nervule bent at an acute angle. Lower disco-cellular nervule so placed as to cause the 

 discoidal nervure to seem to be a fourth median nervule, a structure analogous to that of the anterior wings 

 of the Papilionidae. 

 g, Rudiments of the discoidal nervure, tin: basal part atrophied as in the anterior wings. 



