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VII. A Revision of the Tipulid genus Styringomyia, Lw. 

 By F. W/Edwards, B.A. 



(Published by permission of the Trustees of the British Museum.) 

 [Read February 4th, 1914.] 



Plates XIX-XXV. 



The genus Styringomyia is an unusually interesting one 

 from several points of view. In the first place, several 

 peculiarities of structure give it a most isolated position 

 among the Tipulidae : it differs from all the other members 

 of the family in (1) the largely developed prothorax, which 

 is less reduced than in any other Diptera with which I am 

 acquainted, the nearest approach being perhaps made by 

 Cylindrotoma ; (2) the possession of a very definite chaeto- 

 taxy of the head and thorax, a condition which is extremely 

 rare among the Nematocera ; and (3) the structure of the 

 genital organs, especially the ovipositor of the female, which 

 is very short and complicated in structure, and altogether 

 unhke the ensiform organ characteristic of practically all 

 other Tipulidae, Cyhndrotominae excepted. These struc- 

 tural features make the genus a difficult one to place ; since 

 no alHes can be pointed out it might well be removed from 

 the Antochini (Limnobina anomala), where Osten-Sacken 

 located it, and form a separate division of its own. 



Styringomyia is also interesting from the point of view of 

 variation, owing to its great tendency to form local species 

 or races, but it is also noteworthy that certain species have 

 attained a wide distribution, and occur side by side with 

 a number of different local forms. In the notes which 

 follow these forms have been regarded as distinct " species," 

 because it has usually been found that even slight colour 

 variations are accompanied by structural modifications 

 in the genitalia, but whether these forms can interbreed 

 in nature can only be determined by experiment, while 

 more extensive material is required in order to decide 

 what characters should rightly be regarded as specific. 



The genus was first described by Loew (1846) from a 

 single female specimen preserved in copal ; subsequently the 



TRANS. ENT. SOC. LOND. 1914. — PART I. (jUNE) 



