318 Annals Entomological Society of America [Vol. XV, 



considering the condition existing in other specialized insects. By 

 virtue of the position of the lobes, these designations are logical, the 

 part adjacent to the maxillary palpus is always the galea. In highly 

 specialized insects, as the Diptera, the lacinia is in nearly all cases 

 wanting and where it is present, as in SimuUum and Tabanus, as 

 Peterson has shown, it is greatly reduced and the question may be raised 

 as to whether this is even the lacinia. In most Hymenoptera, the 

 lacinia is greatly reduced and in certain cases, as MacGillivray has 

 shown, the lacinia may be absent. He has also shown that in many 

 species of Hymenoptera, as Macroxyela infuscata, Doleriis nnicolor, 

 Ophion bilineatum and Vespa maculata, the galea is divided into two 

 lobes. This divided condition of the galea is what probably obtains 

 in the Mecoptera; the two lobes represent subdivisions of the galea 

 while the lacinia has completely disappeared. The lobes of the galea 

 (gl) in Panorpodes oregonensis (Figs. 49, 58) are finger-like and setiferous 

 and they are of about the same length. In Panorpodes carolinensis 

 (Fig. 45) the outer lobe of the galea is distinctly shorter. In Bittacus 

 (Figs. 41, 43) and Apterobittacus (Figs. 44, 53), the two lobes are greatly 

 elongated, and the inner lobe is even longer than the stipes. In Merope 

 (Figs. 46, 54), the two lobes have assumed the form of strongly chitinized 

 triangular plates with dense brushes of rather long setse. The mesal 

 margins of the lobes are thick, somewhat fleshy and with numerous 

 minute setae. Figure 55 shows the lateral aspect of the two lobes in 

 Merope. The brush presents a U-shaped appearance. In Panorpa 

 (Figs. 42, 47) and Boreus (Figs. 36, 60), the lobes have been reduced 

 in length owing to the greatly elongated stipes. In Panorpa they are 

 of about the same size and are setiferous. In Boreus the inner lobe is 

 fleshy, setiferous and provided with two rows of strong conical spines 

 arranged diagonally at the proximal end. The outer lobe in Boreus is a 

 triangular plate curved mesad. 



The maxillary palpus (mp) is five-segmented and setiferous in all 

 the species. The palpifer (pf) is chitinous in Panorpa, membranous 

 in Bittacus and Apterobittacus and slightly so in Boreus and continuous 

 with the first or proximal segment of the maxillary palpus. In Panor- 

 podes, the palpifer cannot be differentiated; it is probably merged with 

 the stipes. The maxillary palpi of Boreus differ markedly from those 

 of the other species studied in that the segments increase in diameter 

 distad, the distal segment being not only the broadest but also the 

 longest. 



The maxillee in general are not articulated to the paracoila of the 

 head by a parartis. They are merely connected with the head by means 

 of the maxacorias (mc) which are distinct in all the species. 



The labium (li) consists typically of the following parts in gen- 

 eralized insects: submentum, mentum, and ligula, the latter of which 

 consists of the stipulae, glossy, paraglossee, palpigers and labial palpi. 

 The mentum is in most cases small, completely fused with the stipulas 

 and cannot be identified as a separate sclerite. In both species of 

 Panorpodes (Figs. 45, 49), the area between the stipes and cardines is 

 entirely membranous. This area comprises the submentum (sm) 



