290 Mr. W, Wcscliu on s/jstematic affinities of tlic Phoridas 



foreipcs inter inrcs and palpi f/cnUalinm and contains the 

 penis. Usually these organs are hidden in the cavity of 

 the hypopygiuni. In I\ incrassata are found paired liooks 

 and plates, the latter covered with a minute sculpturing 

 of the chitin identical with that found on parts of the 

 genitalia of rcrip/ancia. These hooks and plates surround 

 the penis, which is formed of a hyaline membrane based 

 on a chitinous ring, and with some structure and tubercles 

 on one side. The ejaculatory duct runs up through the 

 chitinous ring, and opens on the side opposite the tubercles. 

 The penis is asymmetrical, and is the simplest and rudest 

 that I know in Diptera. The spinus (unless it has soldered 

 into the back of the penis, and is present as the "structure" 

 alluded to above), and the apodemes, appear to be absent. 

 7^ coiu'iniM has a more elaborate penis, and its base is 

 fused with a lever which probably represents the great 

 apodemes, and sensory structures represent the palpi 

 genitalium and forcipes interiores, but this last portion of 

 the genitalia is difticult to understand and requires more 

 material for study. In T. (ttcrfiriia, though the containing 

 |)lates of the lower part are easily differcutiated as I'orceps 

 interiores and j^alpi genitalium, the penis is minute and 

 unsymmetrical, and seems to be a membrane based on a 

 ring as in P. incrassata, hut the ejaculatory sac and apodcnie 

 arc quite ohrious. 



A fourth species, P. rnjipes ?, has the penis and sur- 

 rounding parts of another typo. The variations generally 

 are much greater than usually found between species, or 

 even genera in the Muscidaj. One cannot but be struck 

 by the extraordinary anomalies in the parts ; all these 

 insects have the organs representing the forcipes superiores 

 and forcipes inferiores of a more archaic type than those 

 found in the Mycetophilidse, together with (in Trineiira) 

 an ejaculatory apparatus such as is found in the highly 

 specialised Muscidie. 



In Conicera atra, Mg., the genitalia are far more sym- 

 metrical and appear to approximate to the form that is 

 found in the Lonchopteridai, and both suggest a relationship 

 to J)ol ichopms. 



Phe (jenitalia (female). The ovipositor is fairly simple ; 

 it is similar in general plan to that found in the 

 Dolichopodidre, that is to say it is moderately long, pro- 

 trusile, and with distinct joints, but lacking the chitinous 

 rods found in tiie Muscida3. At the distal extremity are 



