80 Annals Entomological Society of America  [Vol. XIV, 
obases”’ of a crustacean limb) form the glossa, “gl,” and paraglossa, 
‘‘ng,” of the labium (see Figs. 6, 10, etc.) The glosse, “gl,” of Fig. 13, 
10, etc., are sometimes referred to as the inner lobes of the labium, 
while the paraglosse ‘‘pg’’ are sometimes referred to as the outer lobes 
of the labium. The sclerite labeled ‘‘ls’”’ in Figs. 10, 6, 18, etc., is some- 
times called the ‘“‘stipes,’’ but since the term stipes is restricted to a 
sclerite of the maxilla, I would refer to the sclerite ‘‘ls’’ as the labio- 
stipes, to indicate that it is a labial structure. The labiostipes “‘ls”’ 
bears the inner and outer lobes of the labium (i. e., ‘gl’? and “pg”’ of 
Figs. 6, 10, etc.) in some insects. 
Various modifications of the above-mentioned structures are met 
with in different insects. Thus in the beetle larva shown in Fig. 8, 
a ligula, labeled ‘‘lg”’ occurs in the region originally occupied by the 
inner and outer lobes (‘“‘gl”’ and ‘“‘pg”’ of Figs 10, 6, etc.), and it is quite 
probable that the ligula “lg” of the beetle larva shown in Fig. 8, (or 
the insects depicted in Figs. 9, 49, 23, 27, etc.) represents the fusion 
product of the two inner lobes (gloss) of the labium, with which the: 
outer lobes (paraglossee) may also have united. In the insects shown 
in Figs. 17 and 15, on the other hand, the ligula “lg” is apparently 
formed by the united glossz only, since the paraglosse “‘pg’’ are appar- 
ently still distinguishable. In most instances, however, the general 
term ligula has been applied to the unpaired median terminal structure 
projecting between the labial palpi (i. e., “Ig” of Figs. 8, 9, 27, 23, etc.) 
regardless of whether it is formed by the united glossz alone, or whether 
the paraglossee have also entered into its composition. 
In the larve shown in Figs. 8, 20, 25, 31, 49, etc., there occurs a 
basilabium, ‘‘prm,”’ or basal labial plate formed by the union of the 
labial stipes ‘“‘ls”’ of Figs. 6, 10, ete. This basal labial plate may also 
include the palpigers in its composition, and is typically a transverse 
chitinization of the area at the base of the labial palpi. In some insects 
it is not demarked from the ligula ‘‘lg’’ (as in Figs. 23, 9, etc.) while in 
others, such as those depicted in Figs. 8, 22, etc., it is demarked by a 
faint line, or is differentiated by a stronger chitinization and pig- 
mentation. 
In connection with the discussion of the terminal region of the 
labium, the spinneret ‘‘spt”’ of Figs. 25, 31, etc., should be mentioned. 
This spinneret is usually closely associated with the ligular region, 
although a portion of the hypopharynx may possibly be involved in 
- the spinning structure. Whether or no the structure labeled “spt?” 
in Fig. 30, iss-homologous with the spinneret of lepidopterous larve, 
is a question which I have been unable to decide, and I have therefore 
merely offered the suggestion as a possibility, rather than as a definite 
opinion in the matter. A comparative study of this region in the 
Trichoptera, Lepidoptera, and other spinning larve is greatly needed, 
and would be of considerable value in the matter of determining the 
affinities of the insects having caterpillar-like larve. 
It is very unfortunate that Peterson, 1916, who follows Kellogg, 
1899-1902, in his interpretation of the parts, did not study the mouth- 
parts of the Neuroptera such as Nemoptera (Fig. 86) and the Mecoptera, 
