48 BRITISH CICADJE. 



thing also may be due to the character of food assimi- 

 lated by the larvae. 



The ponderous synonymy attached to many species 

 of insects bears testimony to the efforts made by 

 late authors to consolidate groups, which almost from 

 necessity have at first appeared under provisional names. 



I think this will apply particularly to those Hemiptera- 

 Homoptera in which salient morphological details are 

 sometimes absent or with difficulty found. 



Where no definite life-history is known, and even 

 the habitat is doubtful, there is nothing but individual 

 opinion to decide on the value of characters ; and 

 where little more than a catalogue, British or foreign, 

 is available, it seems justifiable to fuse, perhaps, two 

 or more species into one, although it may require some 

 courage to do so. Still, in the list I purpose to make, 

 I thus venture, but in no way dogmatically ; leaving 

 to others to show where excision has been carried 

 too far. 



In my opinion John Scott and others have laid too 

 much stress on the slightly altered curves of the edges 

 of the isolated male styles of both Delphacidae and 

 DeltocephalidaB. 



Probably the external apparatus of the reproductive 

 organs of insects are more particularly liable to varia- 

 tion than other parts. The very complex and varied 

 nature of the prehensile and locking action of the male 

 and female parts during coupling, in closely allied 

 species, shows that surroundings have a moulding 

 influence; but until such modification can be shown 

 correlated to other parts, caution must be used, not too 

 hastily to dogmatize. 



The recent researches of M. A. Giard seem to show 

 that, through the destructive action of some particular 

 Hymenopterous parasite, a kind of male castration is 

 effected in certain Typhlocybidae ; and that, in and 

 through some obscure process, degenerated or degraded 

 forms, differing from the original species, may be per- 

 petuated. This remarkable observation will be alluded 

 to further on. 



