i5o 
different (Fig. 60). Here again variations occur in the 
same species. An accurate description of a wing 
should comprise all the minute spots on each vein. 
The Wing Fringe .—Where each long vein meets 
the costal vein (which passes right round the wing) 
there not uncommonly occurs a light area. Note that 
the fringes of M. rhodesiensis , M. funesta , M. listoni , 
M . culicifacies differ from one another (Fig. 59). 
The Leg Bands. —It must be noted whether the 
banding, if present, in each segment (tarsus) is apical 
or basal or both ; whether slight or well marked, etc. 
Thus N. theohaldi has the last two hind tarsi entirely 
white, while N. jamesii has the last three hind tarsi 
entirely white (Fig. 61). 
The Palpal Bands. —The palpi consist of four 
segments. Accumulation of white scales frequently 
occur at the junction of two adjoining segments 
forming a band. Here again variation occurs in the 
same species especially at different seasons of the 
year (Adie), so that in this and other markings, e.g., 
leg bands, species must not be founded on too slight 
differences. 
In M. rhodesiensis the tip of the palpi is black, in 
M. funesta white, so these two species are easily 
distinguished. P. marshallii has two broad apical 
bands and one small basal, while P. costalis (otherwise 
indistinguishable) has one broad apical and two 
narrow basal, but as all transitions can be found 
between these two conditions it is doubtful whether 
they are distinct species (Figs. 60 and 61). 
The Male Genitalia. —It is probable that these 
will give very important aid in distinguishing species, 
but very few data on this point exist. It will generally 
be found necessary to stain and mount the genital 
segments as directed on p. 144. 
