348 ME. WALTER WESCHE ON THE GENITALIA OF 



Musca (PL 26. fig. 60). They are well developed and characteristic in JPolleuia rudis, 

 Eabr., and some species of Lucilia (PI. 26. fig. 62). 



They were described from Calliphora erythrocephala, Meig., where the serrations on 

 the extremities are very marked (PL 26. figs. 68, 71). In Glossina the paraphalli, 

 together with part of the theca, form a framework which supports an elaborate sensory 

 apparatus and protects the orifice of the ejaculatory duct. The serrated structures at 

 the ends of these parts are still to be found at the extremities of the parts in Glossina 

 palpaUs, Des. (PL 26. figs. 63, 69). 



They are present in Anthomyia radicum (Linn.), with curious processes at the 

 extremities (PL 27. fig. 85). 



Sepsidce. — In the Sepsidae there is an aculeated membrane which springs out of the 

 lower part of the theca, which may be homologous with these parts (PL 28. fig. 99 ; 

 PL 29. fig. 101). 



Use. — The use of these various modifications will obviously vary with the type. In 

 Calliphora and Pollenia the shape and the broadened serrated ends, to prevent the 

 extremities slipping, suggest some application where their elasticity would come into play. 

 As to homology with the ovipositor, they may be treated as outgrowths of the theca. 



[g) The Htpophallus. 



Structure and Nomenclature. — Lowne has so-named the excrescences of the theca 

 which project from the front of that part, the long paraphalli starting from the back. 

 It is a paired organ, open in front, but this is only to be seen by a very careful and 

 difficult preparation of the part. It is strongly chitinized, but sometimes shading to a 

 quite hyaline appearance, and usually has a wrinkled surface with more or less minute 

 barbs. 



EmpidcB and Bolichopodklce . — What I have said with regard to the presence of 

 homologies of the paraphalli in the Emjiidse and Dolichopodidse will also apply to this 

 part. 



Muscldce. — In the Muscidse it is generally present; it is evident in Sarcophaga 

 carnaria as the upper of the two anterior processes, cup-shaped in Pollenia rudis. 

 Seen from the front of the organ in Calliphora, it has the appearance of lateral plates 

 (PL 26. figs. 62, 68). In Anthomyia radicum it is well-marked, also in most of the 

 Cordyluridge (PL 27. fig. 85; PL 28. fig. 88). 



Sepsidce. — It is to be seen in Sejisis cynipsea (PL 28. fig. 99), but it is not so 

 obvious in the Nemopoda that is figured (PL 29. fig. 101). 



{h) Spinus titillatorius. 



Structure. — This part is a single unpaired organ, which lends it distinction, that 

 otherwise it might not merit, as it is often absent, even in those families where it may 

 be found in many species. It is situated immediately behind the penis. It is 

 occasionally articulated, at other times it springs from the base of the theca without any 

 suture. It is highly chitinized, but has a tendency to become membranous at the 

 extremity. 



