BOTH THE SEXES IN DIPTEEA. 



383 



This preparation is best suited for examination with a binocular microscope and low- 

 power objectives, and the position of the interior organs can be well seen in a successful 

 slide. It remains to say that when only the chitinous and membranous structures are 

 wanted, dissection is greatly facilitated by 2J- hours' immersion in the potash solution. 



EXPLANATION OF THE PLATES. 



The following letters are used in the female genitalia :- 



a. Valvula inferior, or ventral egg-guide. 



b. Valvula superior, or dorsal egg-guide. 

 d. Aperture of the vagina. 

 m. The apodeme or the double rod. 

 n. Vagina. 



o. Utero-vaginal tube. 

 r. Oviduct. 

 s. Parovarium. 



The following letters are used in the male genitalia 



a. Forceps inferior. 



b. Forceps superior. 



c. Laminae superiores. 



d. Orifice of ejaculatory duct. 



e. Theca. 

 /. Paraphallus. 

 ff. Hypophallus. 

 h. Spinus titillatorius. 



i. Forceps interior. 



t. Tuba. 

 M. Ovarium. 



w. Lamella anterior. 

 ,v. Receptaculum. 

 y. Egg (ovum). 

 s. Glue-gland. 

 x". Rectal papilla {Dolichopus only). 



k. Palpus geuitalium. 

 m. Double apodemes. 

 n. Ductus ejaculatorius. 

 0. Sacculus ejaculatorius. 

 p. Ejaculatory apodeme. 

 r. Vas deferens. 

 s. Paragonium. 

 t. Vas efferens. 

 u. Testis. 



Fis 



8, 



9. 



10, 



IL 



12, 



13, 

 14, 



Plate 23. 



Genitalia of Sciara thoma (Linn.), ^ . 



Genitalia of Bibio hortulanus, Linn., $ . 



Receptaculum seminis of B. hortulanus, Linn., $ . 



Penis and appendages of B. hortulanus dissected out of abdomen. 



Forceps inferior of B. hortulanus ^ . 



Palpus geuitalium of Scatopse notata (Linn.), removed from its place on fig. 7, where it is 



hidden by the forceps interior. 

 The genitalia of S. notata, drawn diagrammatically to show the arrangement of the parts ; 



seen from the ventral aspect. 

 Ejaculatory apodeme of 5. notata, enlarged. 



Diagram of the sacculus ejaculatorius and its apodeme and duct {S. notata). 

 One of the interior hooks in Cule.c (?). 



Extremity of abdomen of S. notata, showing the single receptaculum. 

 Second interior hook in Cide.v (?) . This and that figured as 10 are opposed by a similar pair of 



hooks ou the front of the central organ. 

 Central organ in Cule.v (?). 

 Forcipes superiores of Anopheles cinereus. 



