70 MOSQUITOES OF NORTH AMERICA 
appendage, the clasp-filament (b) and also occasionally certain lobes near base 
or tip (c), designated as subapical or subbasal lobes. There are three sets of 
paired basal appendages, the harpes (d), harpagones (e) and unci (f). The 
penultimate segment generally has a pair of setose appendages, the basal ap- 
pendages (g). In the simplest forms these smaller basal appendages, harpes 
and harpagones are absent, as in Anopheles, though the unci are always present. 
In the succeeding higher forms the harpes appear and still later the harpagones. 
The harpes are present in all the genera above Anopheles, Aédeomyia and 
Uranotenia and are probably homologous throughout the group as they have 
essentially the same form in all, only becoming modified in Culex. The harpa- 
gones, or at least a third pair of appendages, appear in all the highest forms, but 
it is doubtful if they can be regarded as strictly homologous as they seem to have 
arisen three times independently, once in Aédes, once in Culex and once in 
the sabethid line. We have, however, uniformly designated the third pair of ap- 
pendages as harpagones. Several different lines of modifications are found in the 
different groups. The Anopheles are all very simple, having besides the side- 
pieces, clasp-filament and unci, nothing but various spines and hooks without 
forming definite accessory clasping organs. In the most specialized species, 
such as bellator and barberi there is a rounded basal lobe bearing a tuft of long 
hairs. Next to Anopheles in simplicity comes Aédeomyia, in which there are 
present only somewhat complex unci. The side-pieces have a small basal lobe 
while the clasp-filament has a multiple terminal spine. Next comes Uranotenia, 
in which there is a complex series of small basal appendages perhaps represent- 
ing divisions of the unci, but no recognizable harpes. The side-pieces bear a 
more or less well-developed conical basal lobe. Next come the lower Sabethids, 
Lesticocampa and Joblotia, together with the lower Culicids, Megarhinus, Ban- 
croftia, Mansonia and Culiseta. These have the harpes well developed but no 
harpagones. There is generally present a basal lobe to the side-piece, which in 
Mansonia becomes modified into a ribbon-like appendage or a rod carried on the 
basal lobe. In the Sabethid line a division of the small basal parts occurs, so 
that in many forms a third pair of appendages or harpagones can be recognized. 
The characteristic development of the line, however, takes another direction, 
that of the modification of the clasp-filament, which becomes lobed and dis- 
torted, culminating in Sabethes, where a truly wonderful structure is produced. 
In a few forms the clasp-filament is reduced to a rudiment, its place being taken 
functionally by an expanded outer angle of the side-piece, and in others a basal 
lobe of the side-piece is developed (as in Wyeomyia eloisa and allies) in which 
case the clasp-filament is more or less reduced. In the Aédes line the lower 
forms are simple. In calopus there are no harpagones and in other tree-hole 
species the first rudiments of these organs are seen as a conical basal lobe of the 
side-piece bearing a seta (for instance in walkeri, albonatata, etc.). Later this 
becomes developed into a rod bearing a filament. Sylvestris and fuscus have no 
harpagones, but in these cases the organs have not improbably retrograded. In 
the Janthinosoma group the rod bears several filaments and in Psorophora a 
capitate tip is developed with a large group of filaments. The harpagones of 
