18 CLASSIFICATION OF THE ALEYRODID^. 
lost, the cubitus is retained, and no pupal compound wax pores are 
present. This divides the family at once into two distinct sub- 
families to which the names Aleurodicinse and Aleyrodinse may be 
applied. Outside of these two subfamilies we have the form JJdamo- 
selis pigmentaria, which, is much more generalized than any other. 
It retains both media and cubitus and we place it, at present, alone 
in the Udamoselinae. We have included in the Aleyrodinos three 
genera, Aleurochiton, Aleyrodes, and Neomashellia. The first is the 
most primitive, and from it Aleyrodes has arisen by the reduction 
of radius t . Neomashellia, however, seems to have separated earlier 
than Aleyrodes, for it retains very hairy psyllid-like claspers and 
the wing venation is more reduced. The genus Aleyrodes at present 
includes many diversified forms and a careful study of these will 
no doubt necessitate the breaking up of the genus. 
In the subfamily Aleurodicina? the most primitive form seems to 
be Dialeurodicus cocherellii. This species, while it has developed 
the wing venation of Aleurodicus, still retains head characters which 
ally it to Udamoselis. The pupa, too, has no compound wax pores 
as in the genus Aleurodicus. With this species as type, Cockerell 
erected Dialeurodicus and placed it as a subgenus of Aleurodicus. 
It is evident, however, that this does not represent its true position, 
but that it is considerably older than Aleurodicus. We therefore 
make it the type of a genus rather than a subgenus. The species 
described as Aleurodicus laMllei, as discussed under wax pores 
(p. 14), shows characters intermediate between Dialeurodicus and 
Aleurodicus. These characters are so marked and evidently inter- 
mediate that we make it the type of a new genus, Leonardius, allied 
to Dialeurodicus in wing form, vertex, and vasiform orifice, and 
showing a development toward Aleurodicus in wax-secreting struc- 
tures. The genus Aleurodicus is separated at once by the wing 
venation, the definite wax-pore structures, and the long exserted 
lingula. There are, however, forms of this type in general structure 
which have an included lingula and wax pores tending toward those 
of Paraleyrodes. For these forms we erect a subgenus, Metaleurodi- 
cus. This subgenus does not seem to be directly on the line toward 
Paraleyrodes. It is, as far as wax pores are concerned, but the 
lingula seems to place the group by itself. 
The genus Paraleyrodes is plainly derived from near Aleurodicus 
by the reduction of the radius and pari of the media, and by the short- 
ening of the spinnerets and the cup of the wax pore. At the same 
time some of the segments of the antennae have united. It is the most 
specialized genus of the Aleurodicinse as Neomashellia is the most 
specialized in the Aleyrodin». The position of the family and the 
relations of the genera, as we understand them, are shown in figure 1. 
