22 
[June, 
ON MUSCA H OR TOR UM, FALLEN, AND ALLIED SPECIES. 
BY R. H. MEADE. 
It has been well said, that an Entomologist who aspires to be 
anything more than a collector or dabbler in science, must coniine 
himself to the study of one Order of insects ; and if he has but 
little time at his disposal, devote most of his attention to one family 
in that Order : he can only thus acquire an intimate and critical ac- 
quaintance with the characters of the species which it contains, or of 
their life history. 
In many genera there are small groups in which the species bear 
such a close general resemblance to each other, that several species have 
been confounded together by the older authors. This has principally 
arisen from their neglecting to observe and record minute points of 
structure, such as the number and disposition of the hairs and spines 
on the legs, wings, or body of the insect ; which are often exceedingly 
valuable specific characters, being mostly constant, and not liable to 
vary like size and colour. 
The descriptions of the older Entomologists were also generally 
so brief, that they often apply equally well to two or three distinct 
species, and there is very little doubt that they frequently were so 
applied ; the author confusing two or three species. Much learning 
has sometimes been brought to bear on this subject, in the endeavour 
to ascertain the precise species to which a name has been applied ; 
but if this point can be cleared up at all, it must be by the examination 
of typical specimens preserved in Museums.* 
It is to one small group in the restricted family of Mu&cidce that 
I wish to direct attention. In our gardens and groves, and on the 
road-side hedges, a very common fly may be found of a blue-black 
colour, marked wdth white reflections, rather larger than the ordinary 
house fly {Musca domestical), which has been long known as the garden 
flv {Musca hortorum). Upon careful examination it will be found 
that two distinct species (both common in most places in England), 
have been confounded by all the older Dipterologists, and are still but 
imperfectly known, different authors who have distinguished them 
having described them by different names, in ignorance of the writings 
of others ; so that the synonymy is in great confusion. 
Robineau-Desvoidy, in his great work upon the Myodaires, pub- 
lished in 1830, first pointed out that there were several distinct species 
*• Meigen’s collection of Diptera is in the Jardin dcs Plantes, in Paris ; Macquart’s in the 
Museum of bis native city, Lille ; Fallen's is in Stockholm. 
