xvt- 



INTRODUCTION. 



If it be asked what is the most arresting result of our 

 prolonged study of the genitalia of the Tortricidce , we 

 should be inclined to reply, the way in which the species 

 fall into clearly denned groups. In other words, the 

 genitalia are strongly generic in character, and it is possible 

 to place, at once, a species in the group to which it belongs. 

 If it be further asked what light the genitalia shed on the 

 historic relationship of the groups or genera, we have to 

 confess that it is very little. This is not to be wondered at; 

 the fact that the genera are so clearly denned shows how 

 many connecting species have ceased to exist; and, further, 

 the British species form but a part of the whole. Nor is 

 it yet possible to say where the Tortricidre should be placed 

 amongst the Lepidoptera. We find a connecting link with 

 the GeometridcB , where the characteristic hinged, and, 

 much curved penis of the Tortricidce, appears in the 

 Chesiadina, notably in A nail is plagiata, where also there 

 is a kindredship between the females; and in the Tortrix- 

 like form of Odezia at rata; but clearly a phylogenetic tree, 

 from the genitalic point of view, is not yet possible. 



When we come to specific differences the position is 

 quite otherwise. Here the differences, although constant, 

 are sometimes extremely small, and in these cases it was 

 necessary to make many preparations before they could be 

 detected. Within the groups it is possible to secure a 

 perfectly natural sequence. 



In the present volume we have gone further than in 

 the two previous ones, and present a definite scheme of 

 classification, based entirely on the genitalia. We rate 

 very highly the classificatory value of the genitalia, on the 



