W. G. DIETZ 345 



THE HEBES GROUP OF THE DIPTEROUS GENUS 

 TIPULA LINNAEUS 



BY W. G. DIETZ, M.D. 



In his paper entitled, "Tipula fallax and Others,"^ Professor 

 Doane tabulates eight species of Tipula. Five of these he describes 

 as new, the other three — hebes, fallax and grata — had been de- 

 scribed by Loew. These species form a natural group, charac- 

 terized by the structure of the eighth abdominal sternite and of 

 the hypopygium, and which may briefly' be described as follows 

 (see plate XIII) : First — -The posterior margin of the eighth sternite 

 is incised on each side, forming thus three lobes except in new- 

 comeri, the lobes always more or less densely clothed and fringed 

 with hair; Second — -Below the apical appendages the latero- 

 inferior margin of the ninth stelriite has an oval, or approxi- 

 mately circular emargination, filled with a whitish membrane 

 which widens out beyond the posterior margin and forms an 

 appendage, called bj' Professor Doane the lateral appendage 

 and which must not be confounded with the apical append- 

 ages described by Mr. Robert E. Snodgrass.- From the mar- 

 gin of the appendage project processes — called arms by Pro- 

 fessor Doane — generally two or three, called the upper or first, 

 middle or second, and lower or third process, respectively'. In 

 general it may be said that the upper process is always chitinou?;, 

 the middle generall}' so and the lower (third, when present) mem- 

 branous and pendulous. In form these processes vary greatly, 

 and it is here that they furnish the most important characters 

 for the separation of the otherwise very closely allied species of 

 the group. The arrangement of the mesonotal vittae is so nearly 

 uniform as to be almost characteristic of the group. The lateral 

 stripes are described in the text as concolorous and margined with 



1 Psyche, xviii, 160. 



- The Hypopygium of the Tipulidae. Trans. Am. Ent. Soc, xxx, 

 179 et seq. 



TR.\NS. AM. f:NT. SOC, XL. 



