3 LEPIDOPTERA HETEROCRRA 



of vein 2 of the forewings, which is constant, distinguishes the family from all others of the Micro- 

 Ltpidoptera except some forms of the Glyphipterygidae and Xyloryciidae , which are easily known by their 

 pqinted recurved labial palpi, and smooth heads. 



The external relationship of the family appears to be clear; it is a development from the 

 Argyroploce group of the Eucosmidac, the transitional connection (through Mictoueura in the Tortricidae 

 and Articolla in the Eucosmidae) being almost complete. As the Argyroploce group exhibits a not inconsi- 

 derable degree of mo iification rclatively to the Laspeyresia group, which is tiie primitive form of the 

 Eucosmidae, the origin of the Tortricidae in time must be regarded as markedh' later than that of the 

 Eucosmidae. It is diiificult to reconcile this vvith the geographical distribution, but the latter is veiy 

 puzzling on any view. Both families must apparentl)' have originated in the Indian regi(jn. Throughout 

 Europe, Asia, Africa, and North America (South America is at present doubtful) the Eucosmidae predo- 

 minate, outnumbering the Tortricidae in the proportion of three to one. In Austraha and New Zealand 

 the conditions are reversed, the Torfricidae being dominant and outnumbering the Eucosmidae (if recent 

 Indo-Malayan immigrants are excluded) also in the proportion of three to one. Both famihes seem to be 

 well adapted to tropical and temperate climates aUke. The New Zealand Tortricine fauna can be quite 

 satisfactorly accounted for on the view that it is based on the Australian, wilh the addition of a shght 

 South American element. The Australiaii Tortricine fauna liowever consists cjf a larger Tortricid and 

 smalier Eucosmid elements, both of an advanced type and not inchiding representatives of the earlier 

 forms which must have coexisted abundanth- in the region from vvhich this fauna was derived, which 

 must have been the Indian region. The only possible explanation seems to be that the transference was 

 not effected by any nearly complete land connection, but took place across a wide channel of several 

 hundred miles, and that only a few accidentall}' selected forms made tlieir way across. at a period which 

 can hardly be later than the Cretaceous; from this very Hmited and casual immigration the ])eculiar 

 and speciaiised Australian stock was developed. 



I have classed the genera in four groups, to which structural characteristics aie assii;ned. but 

 these are by no means absolute (except the second), and can only be treated as probable indications; 

 they vvill however be found helpful. These are as foUows : 



Qroup A. — Head rather rough, forewings normally with y and 8 stalked Genera 1-20. 



Qroup B. — Head smooth-scaled Genera 21-26. 



Qroup C. — Head rather rough, forewings normally with y and 8 separate Genera 27-5 1. 



Qroup D. — Head rather rough.forewings normally with tufts of scales Genera 52-8o. 



The lowest or basal group consists of Peronea and its alhes ; from this is developed the next group, 

 including Tortrix and its alhes, and froni tliese arise the other tvvo, the small and peculiar tropical Cerace 

 group, and the extensive and mainly Austrahan Capua gronp. 



The discrimination of genera in the Tortriciua lias ahvays been admittedly difftcult ; the similarity 

 of type which prevails throughout the group permits only a few small genera to be obvious, and the 

 classification of the large mass of remaining material has to depend upon structural characteis vvhich are 

 in all instances either subject to variation or indefinite. The stalking or separation of veins 7 and 8 of 

 forewings and of veins 6 and 7 of hindwings, for instance, are variable characters to the extent that in 

 some species of genera to which these are assigned as delimiting characters individual specimens aie 

 found (sometimes not uncommonly) which are abnormal in this respect and do not show the generic 

 character. The structure of the palpi, whether porrected or ascending, naturally differs somewhat in 

 each species, and tends to pass from one type to the other by insensible gradations. The thoracic crest 

 may be very stightly developed, and is then difficult of appreciation. The relation of the termination of 

 vein 7 of the forewings to tlie apex is often wanting in precision, because the apex is more or less rounded 



