( cxv'iii ) 



fied as to form a pair of appendages adapted to act as 

 clasping organs. They could not have served that purpose 

 from the beginning, hut containing, as they still do, the 

 apertures of secretory glands, their development at first may 

 have been to give a more effective use to those glands, and 

 later coming to serve also another purpose their further 

 development may have been in that direction. The genital 

 opening of the male, I may remark, lies just behind the 

 sternite of the segment to which the dorsal processes belong, 

 and is followed by another well-marked sternite which I con- 

 sider to be that of the ninth segment, though much larger 

 than the corresponding tergite. 



There are, as you all probably know well, tw^o principal 

 views as to the origin of the wings in insects, and many ad- 

 vocates of each view. The arguments on both sides are very 

 well set out in a paper on the subject by G. Crampton which 

 appeared in the Journal of the New York Entomological 

 Society in March 1916. The author himself advocates what 

 is, I think, the now generally accepted view, namely that the 

 wings have arisen as out-growths or expansions of the dorsal 

 plates of the meso- and meta-thorax, have gradually developed, 

 and in time became articulated at the base, finally functioning 

 as true wings — that their origin and development was, in 

 fact, very like what we see in the ontogeny of the termites, 

 bugs and other hemimetabolous insects of the present day. 

 To this theory of their origin it lias been objected that the 

 wings must have served some use at every stage of their 

 development, and that it is very difficult to understand to 

 what use the notal expansions could have been put which 

 would have caused them to develop an articulation at the base. 

 Crampton effectively replies to this objection by saying : 

 " If an expansion of the integument can acquire an articula- 

 tion with the body when it develops into a tracheal gill in 

 the water, why can not a similar expansion acquire an articu- 

 lation with the tergum when it becomes a wing in the air? 

 It is surely no harder to conceive of a rigid outgrowth becom- 

 ing an articulated a]>pendage in the air, than to conceive of 

 a similar rigid outgrowth becoming an articulatetl a])pendage 

 in the water ! " 



