Woo. CHARLES Paut ALEXANDER 
(supposition), Rhaphidolabina, Oropeza, Longurio, Aeshnasoma. The 
descriptions for the genera are either entirely new or else the characters 
have heretofore been insufficiently described and figured. The details 
of structure of the head capsules of nearly fifty genera of crane-flies ure 
now known. 
The labrum and the epipharynx.— The labrum is preserved in all crane- 
fly larvae. It is usually broadly transverse or oval. The dorsal surface 
is clothed with short hairs, these being longer on the anterior margin, 
which is often provided also with a limited number of sensory: bristles, 
or papillae. The lateral regions on the ventral, or epipharyngeal, side 
often bear long tufts of hairs. The epipharynx proper is variously armed 
in the different groups of crane-flies. 
The labium.—'The labial region of the capsule is of vast importance in 
classification, and the location of the constituent parts should be early 
appreciated. The confusion in terminology of the dipterous larvai labium 
has been partly outlined by De Meijere (1916:253). The principal 
Synonyms are as follows: 
Submentum. 
Mentum — The pharyngeal plate, or lower lip (Meinert); submentum (Miall); ectolabium 
(Bengtsson); labial plate. 
Prementum — Mentum (Miall); ectolabium (Keilin); endolabium (Holmgren, Vimmer, 
Bengtsson). 
Hypopharynz — Labium (Meinert); mentum (Miall, in Dicranota); endolakium (Keilin). 
The submentum is represented by a narrow transverse strip in the 
eucephalous groups of crane-flies, being well shown in Ptychoptera. The 
mentum is the usually chitinized anterior-ventral plate of the capsule. 
In Ptychoptera it is margined anteriorly with about twenty comblike 
teeth. In Bittacomorpha it is more or less distinctly bilobed, but is 
untoothed. In the generalized Tipulidae it is indistinctly divided into 
an outer plate and, immediately dorsad of this and closely applied to or 
fused with it, an inner plate. The outer plate furnishes the apical median 
tooth of the mentum and in some cases an additional tooth on either ~ 
side. The inner plate adds a varying number of teeth to the mental 
plate, from two in Epiphragma to as many as ten or twelve in some species 
of Limnobia. The chitinized plate is completely divided medially in 
some Eriopterini (Molophilus and some Erioptera), in the Pediciini, and 
in some Hexatomini (Pseudolimnophila). In this case, each half is 
