and of several BrackycGwus families in Diptera. 291 



the usual sensory organs. The receptacula seminis are 

 soluble in the process necessary for preparing the insect 

 for high-power microscopic examination. This is never 

 the case in the Muscidse, with the exception of the 

 Chloropidse. 



In the ovipositor of P. ciirvinenns, Becker, I found a 

 single chitinous rod which appears to be homologous with 

 the apodeme found in the ovipositor of Bimulium reptftns, 

 L., and there are chitinous levers connected with the 

 valves similar to those found in Chironomus, in Gymno- 

 plwra arcvata, Mg., P. lutea, Mg., and P. rifjicornis, Mg.* 



On the extremity of the ovipositor of P. ruficornis there 

 is a chitinous serrated process, and the abdomens of two 

 females contain larvse of an unfamiliar type, and I think 

 that this species is viviparous. 



Those who have had the patience to follow me through 

 these details, necessary to prove my case, will see that in 

 this family are preserved characters of very archaic type 

 in the peculiar bristle structure, in the cerci, and in the 

 Periplaneta-like structures in the male genitalia while 

 other parts approximate to the Muscid type in the ejacula- 

 tory sac and apodeme. In the ovipositor of the female 

 will be found similar anomalies. The ovipositor may be 

 said to be nonexistent in the Nematocera, in the Phoridse 

 it is well developed, yet in some species carries structures 

 only found in the Simulidae and Chironomyidae. 



In the trophi, the presence of two jointed palpi in at 

 least two species, the sense organ in Trinevra and the 

 very general situation of the embedded mandibles on the 

 ventral side are distinctly Nematocerous characters ; while 

 the teeth on the paraglossse are a character only hitherto 

 found in the Muscidas. 



The labrum and hypopharynx are nearer the same parts 

 in the Brachycerous Dolichopodidas and Empidse than to 

 homologous structures in any other family, while the 

 paraglossse and their tracheae are very similar to those 

 of Lonclioptera and Leptis. 



I have lately found in the heads of some Asilidse, Empidae 

 and Dolichopodidce a chitinous bulb at the base of the 

 hypopharynx, connected with that organ by a tube and 

 having some contrivance resembling a valve. It is ob- 

 viously homologous with the pharyngeal pump in Culex, 



* The genitalia of both sexes in Diptera. Wesche, Trans. Linn. 

 Sec. Second series, Zool. vol. ix, p. 363. 



