4 
DIPTERA 
radius is called R, that behind Ri is called cell R,, etc. In the case of the Sciophilinse where Rz+o is 
transverse in position, the small cell is called Rj and the outer cell is Rsfj, for were the vein Rj+j normal 
in position, i. e. longitudinal, this would be the logical nomenclature. The whole of the posterior part 
of the radius consisting of R2-1-3 and R4-1-5 is called the radial sector (Rs). Some writers (Winnertz among 
others) have erroneous^ considered the base of the sector as a crossvein, while they called the true 
crossvein the base of the third longitudinal vein (R_^_|_5). 
Phylogeny. — The Mycetophilidae may be considered as having descended from an ancestral 
form which possessed elongate antennae of seventeen segments, coxae of moderate length and wings with 
a venation resembling that shown in PI. 2, Fig. I, but with a four branched radius as in Pachyneitra 
(PI. 3, Fig. 4). From this form arose the Pachyneurinae on the one hand and a form having the wing 
venation shown in PI. 2, Fig. I on the other. From the latter we may imagine arose all the other 
subfamilies; the Bolitophilinae {Mycetopliaetiis, Hesperinm, Bulitophila); the Mycetobiin^ (PI. 2, Fig. 2), 
in which the base of the media is lost; the Diadocidiiae in which one branch of the radius has disap- 
peared; the Ceroplatinae (through Hesperodes and Apemon) and Macrocerinae, w here a coalescence of a 
section of media and cubitus has taken place;' the Sciophilinae (PI. 2, Fig. 3), in which the M-Cu 
crossvein is absent, and finally the iMycetophilinae (PI. 2, Fig. 4) in which both the M-Cu crossvein 
and the vein R2+3 are lost either by atrophy or by coalescence. In the process of evolution the venation 
becomes simplified, the antennae are shortened, the coxae lengthen, and finally in the most recent genera 
the tibial setae are greatly developed. 
Nomenclature. — It was originally the intention to make no changes in the existing nomen- 
clature, but this was found to be impracticable. As the work progessed changes were introduced for the 
sake of consistency until finally it is believed tjie nomenclature is brought into conformity with the 
rules of the International code. This has occasioned a regrettable though unavoidable transposition of 
names due mainly to the recognition of some of the genera of Rondani. i'he earliest names of Meigen: 
Zehiiira, Polyxena, Euplirosyne and Fiingivoia (published in 1800). have not been given precedent. The 
first two are briefly described but no t3'pe is mentioned, the synonymy of the third is in doubt, and the 
fourth seems to have been used at a still earlier date, but this last point I have been unable to verif)'. 
Besides the substitutions made for names which have been used before {Dzied:ickia and Meiinieria), 
aii.l the introduction of one new one. Apemon, the following transpositions may be noted : Lasiosoma 
(Winnertz) replaced by Sciophila ; Empheria and Sciopliila [in sensit Winnertz) by Mycomya; Anaclinia 
by Neuratelia ; Glaphyropiera by Leia ; and Leia {in sensu Winnertz) by Rondaniella. Empheria and Sciophila 
(Winnertz) have been combined under Mycomya, and Allodia and Bj'achycanijJa under Allodia because 
the characters given for their distinction are inadequate. If these genera must be preserved their 
separation must be made along entirely different lines. Mycetomvza, Rondani (= Mycosia) is probably a 
synonym oi Sciara. 
Diagnoses of the following new species are published in foot notes under their respective genera : 
Palaeoplatyura Aldrichii, Allocotocerajiavescens, Anatella silvestiis, Cordyla voliicris, and Opislholoba ocdlaia. 
TABLE OF SUBFAMILIES 
a. Medio-cuhital crossvein (M-Cu) present; i. e. a vein connecting Ihe media linth 
tlie cnbitns (PI. 2, Fig, I, 2), or these veins contignons for a sliort 
distance at the place inhere the crossvein nsually is. 
b. The radio- medial crossvein [R-M) distinct, not obliterated by the coalescence 
of a portion of radius and media. 
