( clxiv ) 



Myrmica ruginodis, Nylander, 



is quite different in general aspect, though the development 

 is lateral; the apophyses within the lateral plates are, how- 

 ever, as prominent as in Formica, though somewhat smaller. 



Lasius niger, L. 



The organs in this genus whilst still lateral are different in 

 shape and in various particulars. I refrain from describing 

 any of these, as I hope my friend Mr. Donisthorpe will be 

 bringing out his book on this grovip of insects very shortly, 

 when no doubt he will deal with this side of the subject. 



In summing up, so far as my own observations go, I find 

 that the lowly orders such as Thysanura and Collembola have 

 no external clasping organs, there are certain stylets and 

 sensory gonapophyses that are probably excitants. Lubbock 

 (the late Lord Avebury) states that he noticed very little 

 courtship evidenced among them, the most he saw being a 

 slight caressing with the antennae. I should here say that 

 I quite expected to be able to present a more complete set 

 of examples for your consideration, as I had been promised 

 material especially among the less-known orders, but alas, 

 the war entirely upset these arrangements, and now some of 

 my friends are at the front. 



Turning to the Orthoptera (one of the orders I have been 

 disappointed in), there is a combination of primitive with 

 progressive characters; the cerci are strongly developed, 

 whilst the clasping organs are present but probably are in- 

 adequate to be of much functional use. 



I believe that the Thysanoptera have their genitalic 

 characters somewhat on the lines of those obtaining in the 

 Thysanura, and that they are confined to sensory gonapophyses 

 and stylets. 



It will have been seen that there are two quite distinct 

 sets of organs, viz. the sedoeagus with its various parts, and 

 the external clasping organs, the latter being modifications 

 in all probability of the ninth and tenth abdominal segments. 

 Originally, I have little doubt that the anus had its own pro- 

 tective armature, whilst the sedoeagus had its own armature, 

 the former being confined to the tergite and the latter to the 



