( cxxviii ) 



apical one not half tlie size of the rearward one, and termin- 

 ating in a setose bluntly pointed lower apex and a somewhat 

 excised and dentate upper apex; in the rear these are joined 

 so as to form a short, broad tube, with a hole through which 

 runs the long narrow sedoeagiis with its pair of long, very 

 narrow, tapering apophyses. 



This species is an excellent example whereby we can trace 

 the line of development that might take place from these 

 lower and more complicated structures to the simple forms 

 that we see in the Rhopalocera, especially in some of the 

 Nymphalidae and Ruralidae. In the tergite the gradual loss 

 of the dorsal protection to the uncal arrangement, and its 

 replacement by the anal armature in a more robust form, 

 needs absolutely no imagination, and the gradual fusion of 

 its laterals and of the gnathos into a reduced cingula is equally 

 obvious, whilst the reduction of the harpago by its end segment 

 is likewise obvious and very advantageous. 



Limnophilus flavicornis, F. 



In contrast with the preceding genus Limnophilus has very 

 large dorsal armature and insignificant harpagones, whilst the 

 cingula maintains its segmental distinctness in a yet more 

 primitive manner, for we have the separation of the sternite 

 and tergite quite apparent. The sternite cingula is very 

 broad indeed and expanding forwards, whilst that in the 

 tergite is reduced to a very small hooded structure lying 

 between the subdorsal armature ; the tegumen proper is 

 absent, its place being taken by broad lateral plates each of 

 which forms an ample hood with a serrate fore apex, within 

 which, articulated to its rear, lie two straight tapering horns 

 ending in a blunt point. The harpagones are exceedingly 

 small, placed in an upright position parallel with the cingula, 

 with the apex bent round to the front, terminating in an 

 irregular cuneiform apex ; the sedoeagus with its usual short 

 basal sac is of moderate length, upturned into a sharp rostrate 

 apex, and having two long straight formidable spines. The 

 two apophyses are even longer, and terminate in an elaborate, 

 hollowed comb-like apparatus, that is well haired below the 

 long terminal pectinations. 



