156 
PSYCHE 
[December 
basal cell the ‘posterior cross-vein,’ when it is very evidently homologous with the 
inner vein only, the ‘anterior basal cross-vein’ of Loew, and that is the name that 
should be given to it, if we are to use these systems of nomenclature. A moment’s 
consideration will convince the observer that tlie real po.sterior cros.s-vein of other 
flies is present only in the Tipnlidae and Rhyphidae among nemocerous flies. 
Again, in all the brachycerous flies that have the tliird vein furcate, the cells 
situated between the second vein and the posterior branch of the third are generally 
known as nuhmarginnl cells, either the ‘inner’ and ‘outer’ or first and second, and of 
course, as in Hypcralonia, the third and fourth sometimes; while the cell between 
the first and second vein is known as the marginal in the Loewiah nomenclature. 
In the Nemocera again, misled l)y ( )sten Sacken’s perplexities, the invariable usage 
is to call the cell formed by the furcation of the second vein the first submarginal. 
In the exceedingly rare in,stances (Rrotop/a.vto, etc.) in which the third vein is sup- 
posed to be furcate in the Tipnlidae (Jsten Sac'ken gave the name of supernumerary 
first po.sterior cell to the second submarginal. The culicidologists speak of the 
‘first submarginal cell’ as being longer or shorter than the second basal; what of 
course is meant is the ‘.second marginal cell.’ 
It is rather a curious fact, for which I can offer no explanation, that the second 
vein is never furcate among brachycerous flies, while on the other hand the third 
vein is, I believe, never furcate among" nemocerous flies, with the possible exception 
of Proto'pla.'ita and its allies ainl Psychoda and Pericoma. We find, it is true, an 
apparent anterior branch of the third vein in many INIycetophilitlae, Ribionidae, 
etc. But, I believe that in every such case this so-called anterior branch is in reality 
the second vein, which is ahvays otherwise wanting in nemocerous flies having a 
so-called branch to the third vein. Com.stock’s homologies arc here also more correct 
than is the common usage. A good example of this shortened second vein will be 
found in Paltostoma among the Blepharoceridae, and indications also may be found 
