insipriif icant body parts raay possess so'ne value 

 for the separation of the s:Tecics; ne-^^rrtheless, 

 it is a v/ell-known fact whioh -wi"! I be stiTl further 

 denonstrate-d that the arran^':e;nent of the species 

 according to the de\^lopment of the important body. 

 parts, beside beinr; a iTecessarj'- oart of our system, 

 does present the best base for an equally adequate 

 and clear specific de ter mi nation. It is moreover 

 unquestionable that the only way in which the 

 general ide a of major group can be conceived is 

 through the minor groups in which the idea is differ- 

 ently modified. Vvere the s )ecies mingled together 

 in an arbitrary way then the student of a genus 

 would in his ov^^n aind have to ar r ange the ra in 

 groups be före he could get aiw real conception of 

 that genus. Such minor groups, however, must, like 

 the major groups, be natural. The classical rule 

 for the formation of the najor groups is valid 

 al so for the minor groups and can, applied on the se, 

 be for/nulated as: 

 Sectio dabit caracterera, nec caracter sectionem". 

 If the sections are established according to 

 this rule then it would be possible - v^ith a 

 modification of the classif ication - to divide the 

 genus of which they are oarts into a corresponding 

 numbe r of subge ne ra . 



As Tiev^ genera can only such v/e 11 def ined natural 

 groups be recognized which either de via te funda- 

 mentally from the genus in which they have had their 

 place, or which constitute a hitherto unknovrn 

 group of higher rank. 



The following attempt to build a systematic 

 arrangeraent of the Dipterous family Ephydrinae Zett. 

 on the princioles discussed, is considered as 

 further development, due to new observations and 

 discoveries, of the first paper on this family 

 which 30 years ago was published in Kongl. \etenskaps 

 Akademiens Handlinger by the founder of the owedish 

 Dipterologist. Låter Dipterologists have admittedly 

 greatly contributed to enlarge the rnultiplicity of 

 the members of the family Ephydrinae bur for science 

 these additions have been al nost v/orthl ess . 



