750 CHARLES PAUL 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 are 

 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 larval 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). 



Hypopharynx Labium (Meinert); mentum (Miall, in Dicranota); endolabium (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 



