THE SYRPHIDAE OF OHIO 13 



In Ohio, so far as I can determine, Professor James S. Hine has been 

 the principal worker. An early state list of 25 species was published by 

 him in the Proceedings of the Ohio Academy of Science, Vol. II, pp. 48- 

 54, 1899. A. later list of 92 species was read by him before the Ohio 

 Academy of Science in 1902. Mr. Chas. Dury of Cincinnati has a State 

 collection of 75 or 80 species among which are a few not listed from any 

 other part of the State. 



SYSTEMATIC POSITION 

 The Syrphidae is one of the four families belonging to the Cyclor- 

 rhapha which have no frontal suture (Fig. A ): the other three are 

 the Pipuncnlidae, the P/atypezidae, and the Phoridae. 



The Cyclorrhapa is that group Fronta^Lwule 



of Diptera in which the adults / proji'tal Su^uVR 



emerge from the puparium — 

 which is a pupa-case made by the 

 induration of the last, unmoulted, 

 larval skin — by pushing off in 

 front a circular disc-like opercu- 

 lum. In the contrasting group, 

 the Orihorrhapha , the adult es- 

 capes from the pupa-case thru 

 a T-shaped antero-dorsal orifice 

 made by two splits, one length- 

 wise, the other transversel}'. 



Fig. A. Head of a fly 



In the great majority of the Cyclorrhapha the operculum is forced off 

 by expan.sion of a bladder-like body, tho: ptilinuni , which is protruded 

 thru a suture above the antennae of the nymph, known as the frontal 

 suture. In the four families mentioned above the frontal suture is absent; 

 there is no ptilinum; and the operculum is pushed off, along a line of 

 weakness, by expansion of the face below the antennae. This is proba- 

 bly responsible for the great amount of structural variation to be found 

 in the face of the adult Syrphidae which is often of much use in classifi- 

 cation. 



The four families mentioned above are usually placed at the beginning 

 of the Cyclorrhapha, and in some respects they are intermediate between 

 this group, as a whole, and the Orthorrhapha. 



Verrall locates the Syrphidae between the Pipuncnlidae on the one 

 hand (with which, according to (lirschner, they arc connected tliru 



