352 ME. "WALTEE WESCH£ ON THE GENITALIA OP 



preparation of -S. cynipsea, Linn., whicli appears to sliow them, but unfortunately the 

 bases cannot be seen. They are certainly absent in many species, and the laminae 

 superiores have developed bunches of hair, and in at least one case (PI. 29. fig. 103) 

 tubercles which appear to be sensory, to compensate. 



Ephydridm. — Though the forcipes interiores are present in Farydra coarctata, there 

 are no signs or remains of the palpi (PL 29. fig. 111). 



Use. — These organs fulfil an important oflice, as when they are absent we find 

 compensating sense-organs. In Tipula oleracea lateral bunches of hair, in Pandora 

 scutellaris processes on either side of the theca, six bunches of fine black hair, and in 

 Nemopoda elaborated laminae superiores. 



{in) The Apodemes of the Penis, the Double Apodeme, 

 OR THE Great Apodemes. 



Striicture. — These are the organs (or organ) that rotate the penis, often considerably 

 elongating it in the process. They are found in three conditions : (1) as symmetrical 

 paired organs, as in Sibio hortulamis, Gynoplistia hella, or Tabanus bromiiis ; (2) as 

 partially fused together, as in Glossina or Sepsis ; (3) or fused or " united in the 

 median line " as Lowne puts it, speaking of the part in Calliphora *. 



The part has a markedly laminated structure ; when it is fused, a highly chitinized 

 process runs longitudinally through the middle; it is fitted for the attachment of 

 muscles. 



Nomenclature. — Lowne calls these parts the " great apodemes " : it is necessary to 

 have an adjective to distinguish them from the apodeme of the ejaculatoiy sac, which is 

 often very large and prominent ; as I have found this part separate in several families I 

 have suggested the name of the " double apodeme " to distinguish it from the other 

 apodeme, which is always single. 



Mycetopliilidce. — There are indications of the presence of such an organ in my 

 preparations, but not sufficiently definite to quote. 



Bibionidce. — In JBlbio the theca is attached to two strongly chitinized levers, not 

 shown in the figure. In Scatopse notata the apodeme is fused. These extraordinary 

 anomalies are quite in keeping with what I found while working on the homologies of 

 the mouth-parts. JBihio had a type of trojihi approximating to that in the Muscidse, 

 differing in this from nearly all the Nematocera, and in the Empidse the genus Hybos 

 differed in arrangement from the other genera in the family f. 



Cnlicidce. — I have a preparation of Dinocerites cancer, Theobald, which shows two 

 powerful apodemes placed laterally, and articulating on to the two processes which 

 support the membrane of the penis, also one of Culex (?) which has the apodemes of 

 exactly the same type as Gynoplistia. 



Tipulidce. — In Tipula oleracea, as I understand the apparatus, the long flagellum is 

 pushed forward through the aperture in the theca by the rotation of the ejaculatory sac, 



* ' Blow-fly,' p. 743. 



t " The Mouth-parts of the Kemoctra," Journ. Eoy. ilicr. Soc. 1904. 



