Mr. C. G. Lamb on Exotic ClilovopiJae. 35 



Sitdii a sequence of events is, from the nature of the case, 

 inevitable, though it leads to much difficulty both in tracinj? 

 species and in assigning genera. The fact is that in some 

 groups of the Oscininse there is no natural line or lines of 

 demarcation ; even the known forms merge into one another 

 and share characters that should belong to different genera 

 as originally defined ; and when the world Forms are really 

 adequately studied there can be no doubt but that this 

 tendency will be increased. 



It will follow that it is quite possible that the author may 

 have assigned species to definite genera which, in the opinion 

 of more experienced students, should be placed elsewhere. 

 For this reason the descriptions are often made a little 

 fuller than would be necessary to enable one to discriminate 

 between the species of a sharply bounded genus such as 

 Chyliza. For the same reason it will be found that he has 

 been compelled to place species in genera whose specification 

 does not exactly meet the case. A good example is Lagaru- 

 ceras anumalum ; if the head were removed it would be 

 impossible to distinguish this species from one of the 

 described forms of Becker's L. merfulops ; but the antenna 

 and vertical triangle are both considerably at variance with 

 the forms described as characterizing the genus. Wide 

 interpretation of generic limits is unavoidable in this family, 

 for if definite and fixed generic characters were to be adhered 

 to, the family would mainly consist of monotypic genera. 



The author hopes to be able to continue with some other 

 of the Acalyptrate families if time and opportunity permit. 



Note. — To save space certain abbreviations will be used. 

 When describing the head the word "^ triangle '^ will refer to 

 the fronto-vertical macula usually found there, though its 

 shape varies greatly. The antennal joints will be referred 

 to by number only — thus "3rd" Avill mean third joint of 

 the antenna. In tlie case of the thorax the word^' callus" 

 will refer to the front thoracic callus unless qualified. In the 

 wings the veins will be referred to by the old system of 

 numbers as being more convenient and simple in this case ; 

 thus, " 2nd " will mean the second long vein. Similarly, the 

 costal segments will be referred to by the numbers of the 

 long veins that end there — thus "2 to 3 " means costal 

 distance between ends of second and third long veins 

 measured on costa. 



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