336 Mr. F. W. Edwards’ Notes on British Mycetophilidae. 
indisputable, then the person who first subdivides the genus 
may affix the original name to any portion of it at his 
discretion, and no later author has a right to transfer that 
name to any other part of the original genus.”* Curtis 
specified L. fascipennis as the type ‘of the genus Leia, but 
did not subdivide it; Rondani specified L. bimaculata as 
the type and renamed the genus Leyomya, but Winnertz 
was the person who first subdivided Leva, and his interpreta- 
tion therefore takes precedence above all others. The 
attempt to use the name Leva in another sense arises 
entirely from a misinterpretation of the rule quoted 
through ignoring the word “original.” Rondani’s 
Levomyra (the corrected form of Lejomya) is evidently the 
same as Winnertz’s Glaphyroptera, and so must be used, 
both because it is the older and because Glaphyroptera 
is preoccupied.t+ 
Although these notes are far from complete, it is hoped 
that they will enable collectors roughly to place their 
specimens, and at least in the genera Bolitophila, Macrocera, 
Platyura, Sciophila, and Mycetophila, to determine them 
with some degree of accuracy. Certain species of these 
genera, and the majority of those in the other genera, can 
only be properly differentiated by a microscopic examina- 
tion of the male hypopygium, and it is frequently necessary 
(particularly in the genus Boletina) to remove this organ 
and mount it in balsam (after clearing with potash) before 
its structure can be properly ascertained. ‘The figures of 
hypopygia here given have been prepared from specimens 
mounted in small drops of stiff balsam, placed (without 
cover-slip) on small strips of transparent celluloid, which are 
kept on the same pin which bears the remainder of the insect. 
The table of genera may be useful to those who do not 
possess Johannsen’s monograph in the Genera Insectorum. 
In this key an attempt has been made to use only those 
characters which will group the genera according to natural 
relationships, but as Johannsen has suggested, it is highly 
probable that the Mycetophilinae is of polyphyletic origin 
and therefore in a strictly scientific arrangement should 
be divided into two or more groups or else united with the 
* Brit. Ass. Rept. 1842, p. 111. Although the wording of this 
rule was altered in 1905, the general sensé remains the same and 
the words italicised here are still retained. 
+ This is not the case with Leia. The coleopterous genus of the 
same name was not published until 1821. 
