Introductory 



meut has been along- a different line. It might be more logical to 

 consider the Membracidae as a mere subfamily of the Jassidae, and 

 the}' are retained here as a separate family more out of deference to 

 common usage. A critical study of the whole of the Homoptera may 

 result in dividing the Fulgoridae into two or possibly three distinct 

 families and in leaving the Membracidae and perhaps the Bytho- 

 scopidaej Cicadellidae and Jassidae as distinct families under a super- 

 family Cicadelloidea. Kirkaldy divides his Fulgoroidea into eight 

 distinct families, but gives no characters from which we can judge 

 of the value of his scheme and his divisions certainly are of unequal 

 value. Kirkaldy also claims that the Gyponini have very little to do 

 with the Cicadellini but he fails to give his reasons, merely rejecting 

 the position of the ocelli as a character of any real importance. But 

 this character certainly' has more value than the horizontal extension 

 of the head and I propose to retain my classification of 1892 until 

 some reason is advanced for rejecting it, merely changing the value 

 of the several groups. I might add that the division Dorj^diaria is 

 sufficiently distinguished by the venation, although the flattening 

 of the head is characteristic, and that the Bythoscopinae in their 

 larval and other characters are allied to the Membracidae and serve 

 to connect them with the Jassidae. 



In selecting the references to be included in this catalogue it has 

 been my object to take such as will show the histor}^ and standing, 

 not only of each species and genus but also of the higher groups. 

 Here for the first time the history and synonymy of the group names 

 higher than the genus have been worked out with as great care and 

 accuracy as in the case of the genera and species. If this effort will 

 help in any measure to stabilize family nomenclature, it will well 

 repay the time and space required. I have rejected as illogical and 

 contrary to the accepted rules of zoological nomenclature Kirkaldy 's 

 system of founding the family name on the oldest genus-name in- 

 cluded and have adopted Dr. Horvath's system by which we give 

 priority to famih^ names the same as we do to the names of genera 

 and species; and, Avhat is really the foundation of the system, we 

 give to each family a type genus and the family name follows that 

 of the type genus through all its subsequent changes. For example 

 the family Gelastocoridae was founded as Galgulidae with Gaugulus 

 as type genus. When it was found that the name Galgulus was pre- 

 occupied and the genus was renamed Gelastocoris the family name 

 automatically became Gelastocoridae, instead of taking tlie next oldest 



