SCALH INSECTS OF THE GENUS PARLATORIA 3 
STRUCTURAL CHARACTERS CONSIDERED IN THIS STUDY 
EYESPOT 
The eyespot, if correctly interpreted throughout all the species 
studied, shows differences that appear to have definite usefulness for 
the differentiation of some of the species. In two, blanchardi and 
zizyphus, it is a large, conspicuous, sclerotized area, on the surface 
of the derm in the case of blanchardi and at the apex of a prominent 
globular marginal lobe in the case of zizyphus. In all the other species 
it is much smaller and sometimes very obscure and possibly lacking. 
In two forms, crotonis and proteus, this structure, if correctly in- 
terpreted, appears as a stout spur, decidedly variable in size, that 
protrudes from the prosomal margin on each side in normally 
oriented specimens. In some of the other species the spot appears 
only as a tiny, flattened disk, but in some it may be a protruding 
structure, hemispherical to conical to short cylindrical in shape. 
SPIRACLES 
The spiracles themselves do not appear to possess differences in 
structure that are of taxonomic significance. 
The anterior spiracles are regularly accompanied by multilocular 
disk pores. The average number of these present is reasonably con- 
sistent for any species, but the individual variation within the species 
is such that little taxonomic use can be made of this average condi- 
tion. The number of pores observed in the course of examination of 
material ranged from 1 to 11. 
A curious structure appears in more or less obvious association with 
the posterior spiracles in some of these species. It is a membranous 
imvagination of the derm, located between each posterior spiracle 
and the body margin at a "point varying with the species and from 
one-quarter to one- “half of the total distance away from the spiracle. 
No evidence has been obtained as to the function of this structure, 
and it 1s somewhat irrational to utilize it, both on this account and 
because it is difficult to observe with certainty in poorly prepared 
specimens. At the same time, after hundreds of specimens have been 
examined, it seems to be as nearly constant in its presence or absence 
as are the spiracles themselves; and in view of the variability that 
exists in other usable characters, this one should certainly be utilized 
fully if future studies confirm the conclusions here formulated re- 
garding its occurrence. 
DUCT TUBERCLES 
The duct tubercles are prominent, conical, sclerotized protuberances 
along the margins of the anterior body segments. They vary much 
in shape from flattened conical to elongate, almost cylindrical, and 
hkewise are apt to show decided shape variation in any single speci- 
men. At the same time the general characteristics of these “tubercles 
seem to be reasonably consistent for any species, and they serve as 
supplementary characters that aid in the recognition of some of the 
species. 
From this study these structures occur normally in clusters on 
each side of the body, one cluster on the margin anterior to the an- 
terior spiracles, one directly opposite the anterior spiracles, one in 
