148 THE CANADIAN ENTOMOLOGIST. 



species. The different elements among the numerous genera need 

 bringing out, but it has been sufficiently shown here where the general 

 lines of relationship are to be sought. Like the Hawk moths, these too 

 have been redistributed by climatic changes, the most important of which 

 was the Glacial Epoch. We receive a large accession from the south, 

 but the bulk of our Noduidce show a northern parentage. The common 

 ancestors of certain of the European and American Owlet moths of to-day 

 had, at one time, a common sporting ground. I have shown the existence 

 of every grade of resemblance from undistinguishable species like Scoliop- 

 teryx libatrix and Dipterygia pinastri, through slightly modified forms 

 like Apatela occidentalism Dianthoecia bella, Copimamestra occidental 

 Agrotis normaniana, Lithophane Thaxteri, to forms readily distinguish- 

 able in all their stages by the experienced student. The mass of species 

 is so great that detailed observations on each particular one must await 

 time ; but I trust I have laid down the lines by which our Owlet moths 

 are to be studied until our information with regard to them is perfected. 



Some idea of the preponderance of Catocaimce in North America may 

 be given by the statement that in Europe there are about fifty-six species 

 belonging to about sixteen genera, while in North America there are about 

 two hundred and fifty species belonging to about fifty-six genera. These 

 latter figures may be changed by new observations with us, but hardly 

 diminished. In the Deltoidiiice the proportions are more in conformity 

 with the numerical relations in the typical group, the Noctuince. The_ 

 reason I have given for this preponderance of the Catocalince, lies in the 

 physical geography of the continent, the prevailing atmospheric and ocean 

 currents, all of which favor the introduction of southern or tropical lepi- 

 dopterous forms. And we must consider the Catocalince as tropical in 

 general character in the same way as we consider the other groups of the 

 Noctiiidce as belonging to temperate regions of the earth's surface. 



In a general view of the evolution of the Lepidoptera we may conceive 

 it as represented by an inverted and spreading bell of net work, in hang- 

 ing threads of unequal lengths, branching variously and in different direc- 

 tions, and ever widening in departure and circumference. The depend- 

 ing tips of the threads represent the existing species, all connected with 

 the past, and the task before us is the tracing of the threads, always run- 

 ning here and there together, grouping themselves about thicker strands, 

 converging in the hand of time. The means at our disposal for the un- 



