1922] Otanes: Head and Mouth-Parts of Mecoptera 319 



and the labicorise (Ic), the membranes which connect the maxillcC and 

 the labium in all generalized insects where the submentum is a distinct 

 sclerite. In Panorpa americana (Fig. 48), the submentum is membranous 

 except the ventral portion, which is distinctly chitinized. This chitinized 

 portion of the submentum was designated as the mentum by Crampton 

 (1921) in his figure for Panorpa lugubris, not indicating, however, the 

 submentum. I have also examined specimens of the labium, as well 

 as other parts of the head, of Panorpa lugubris and have not found 

 marked morphological differences between it and that of Panorpa 

 americana. The labicorias of Panorpa americana, as in Panorpodes, 

 are continuous with the submentum. In BUtacus (Fig. 19) and Aptero- 

 bittacus (Fig. 44), the chitinized portion of the submentiun (sm) is an 

 elongate area, vase-like in outline and bears long, prominent setcE. 

 The ventral portion of this area was likewise designated by Crampton 

 (1921) in his figure for Bittacus (species not indicated), as the mentum, 

 labeling the dorsal portion of it as the submentum. Hine (1S98) in 

 his figure of the labium of Bittacus strigosus, showed the area between 

 the stipes and cardines, considered as the submentum and labicoria in 

 this paper, as if it were wholly setiferous and failed to indicate the 

 chitinized area, which is rather distinct. Hine further considered 

 the ligula as being absent. In Merope (Fig. 40), the submentum (sm) 

 and labicorise have become strongly chitinized, except the portion 

 between the cardines. In Boreus (Fig. 36), the area has become com- 

 pletely chitinized and fused with the stipes. We have thus in the 

 Mecoptera a modification of this area from a wholly membranous to 

 a wholly chitinized condition and also a condition where the maxillas 

 are distinctly differentiated from the labium in one case and another 

 where they are distinctly continuous with it. 



There is a subquadrate area distad or ventrad of the submentum 

 which consists of the fused stipulse, palpigers, glossse and paraglossse. 

 This area is here designated as the mecaglossa, because it is typical 

 of the Mecoptera. The palpigers (pp) are represented in all the figures 

 as occupying the distal portion of the mecaglossa and include the 

 somewhat membranous areas at the proximal ends of the labial palpi. 

 Crampton (1921) calls the mecaglossa in Panorpa lugubris the palpigers, 

 although, he savs, they may represent the basal segments of the labial 

 palpi. In his figure of the labium of the same species, he shows a 

 distinct suture between what he calls the palpigers. Besides Panorpa 

 americana, I have also examined numerous specimens of the labium of 

 Panorpa lugubris and I was unable to find a suture dividing what he 

 terms the palpigers. What appears to be a suture is a thickening 

 formed by the fusion of the tendons which control the movement of 

 the labial palpi. There is a depression along the region he indicates, 

 but it is such a broad depression that it can not be called a suture. 



The mecaglossa is very different from the stipulse, glossae and para- 

 glossce of generalized insects where there is a palpiger attached to 

 the lateral margin of each stipula. It is a greatly reduced area in the 

 Mecoptera and the palpigers are distal in position. The obsolescence 

 of the sutures separating the glossse and paraglossse from the stipulse and 



