342 MR. "WALTER WESCHE ON THE GENITALIA OF 



(b) FORCIPES SUPERIORES Or VALVULE INTERNA. 



Structure. — These so-called hooks are mostly (exceptions will be found in some 

 CulicidiE and Tipulidae) valves, which are generally covered with hair, or bulbous and 

 palp-like in appearance, suggesting a sensory function. 



Nomenclature. — Lowne is responsible for calling them valves, Dziedzicki for the first 

 name. 



IlycetopldUdce. — In Phronia and Sciara they are hairy bulbs (PI. 23. fig. 1). 



Bibionidce. — In Scatopse notata (Linn.) they are large plates, quite overshadowing the 

 usually more prominent forcipes inferiores (PI. 23. fig. 7). 



Cidicidce.- — In the Culicidae they are very elaborate ; in Culex pipiens they are large 

 and are fitted with modifications of setse, several knife-like and one leaf-like, and have 

 besides single large hooks articulated on to their extremities (PI. 23. Kg. 16). Anopheles 

 chiereus has also a hook articulated to the forceps, but is in other respects simpler ( PI. 23. 

 fig. 14). 



Tipulidcp. — In the Tipulidae they consist of large hairy plates as in Tipmla oleracea 

 (PL 24. fig. 22), of plates with an articulated hook as in Gynoplista bella, Westwood 

 (PI. 23. fig. 19), or a more foliaceous form as in Ftychoptera scutellaris, Meigen (PL 23. 

 fig. 17). 



Strationiyiida;. — In the Stratiomyiidse they are hairy and thinner in proportion to 

 tlieir length than in Sciara, 



Tabanidcp. — They are represented by two hairy bvilbs in Tabauus bromiiis, Linn. 

 (PL 29. fig. 109). 



Asilid(B. — They are relatively very large in the Asilidae (PL 24. fig. 37). 



Empidce. — A very marked form is seen in Empis stercorea, Linn. As a rule it is much 

 less developed in this family (PL 25. fig. 40). 



DoUchopodid(B. — Of all the families in Diptera they are in most extraordinary 

 development in the Dolichopodidae. They form the fans that have earned this tribe 

 the popular name of the " fan-tailed flies." They are in their greatest relative size in 

 the genera DoUchopus and Poecilobothrus (PL 25. fig. 43). 



SyrpthidcB. — They are variable, but never very prominent, in the Syrphidae. In 

 Eristalis tenax (Linn.) they are represented by two small hairy processes between the 

 larger forcipes inferiores, which in this case are much like the f. superiores in shape and 

 structure ; they are more developed in Syrplms pipiens, but still smaller than the 

 f. inferiores (PL 25. fig. 55). 



MuscidcB. — They are hairy valves in the Muscidae, which have the anus at their base 

 and close over and protect the penis. Sometimes they are fused as in Rutilia splendida 

 and Olivieria lateralis, Fabr. (PL 30. fig. 120), or absent as in Glossina *, w^here they 

 are represented by two rows of hair on either side of the median line. 



Cordyluridce. — In Norellia spmimana, Fallen, there is rather a characteristic armature 

 (PL 28. tig. 91). 



Use and Homology. — This part seems to act either as a protection to the genitalia or 



* " Genitalia of Q. pal^alk," W. Wesche in Journ. Quekett Micr. Club, no. 57 (Nov. 1905). 



