THE CANADIAN ENTOMOLOGIST. 171 



secure tube for the eggs, I was not permitted to see. The eggs laid in 

 September remained unhatched in the tubes until spring. 



Fig. 3 of the tin-type represents the remarkable frontal " spine " of the 

 moth, by means of which it rips open the pupa cell in the stem of the 

 Typha and escapes. Fig. 4 represents the same of N. typhce, and fig. 5 

 that of JV. subflava. That of the last is hardly bilobed ; under an inch 

 objective, however, the apical notch appears. Only one examined. 



The tin -type showing the structural details was examined by the 

 members 



Mr. J. B. Smith said that the clypeal modification referred to was not 

 peculiar to this species, but was shared by all others of the same genus. 

 Clypeal modifications were very common throughout the Noctuidse ; 

 indeed almost universal in species living in the stems of plants where the 

 insect had obstructions to overcome in emerging from the pupa. 



Mr. Smith exhibited six large photographic plates of Agrotis, illus- 

 trating a large number of species, and made some remarks on the great 

 structural variability of the group Agrotis. Fully 26 groups based mostly 

 on structural characters were indicated. Spinulation of tibi», structure 

 of front, vestiture, form of wings, antennal structure and general habitus, 

 all are variable, and so gradual are the gradations that generic types 

 can not be well founded on them. The plates were examined by the 

 members, and it was agreed that they were fine specimens of the photo- 

 grapher's art as applied to this branch. 



Dr. Morris asked whether the tendency had not been of late to an 

 unnecessary increase of genera in all orders. 



Mr. Smith said that as to the Noctuidae undoubtedly genera were based 

 upon apparently insufficient characters, but less so than in Coleoptera. 



Dr. Horn said it was a principle long since laid down by Lacordaire 

 that characters scarcely of specific value in one group formed excellent 

 bases of even higher divisions in others ; in his view genera are established 

 for convenience merely and have no existence in nature. Nature has only 

 species, and genera were simply useful in dividing the mass of species to 

 facilitate recognition. However, of late, as new material was becoming 

 more scarce, persons seized with the ;;///// itch were taking to describing 

 genera; for some 12,000 species of N. A. Coleoptera, fully 2,000 genera 

 were described. 



Dr. McCook said that in ants and spiders there is plenty of oppor- 

 tunity for persons afflicted with that itch, as there was a very large un- 



