1922] Otanes: Head and Mouth-Parts of Mecoptera 321 



SUMMARY. 



Of all the genera represented in this study, namely: Panor- 

 podes, Bittacus, Apterobittacus, Merope, Panorpa and Boreus, 

 the first one, Panorpodes, is the most generalized. The head is 

 orthopteran in form and does not have a trunk-like beak. 

 Boreus and Panorpa are the most specialized, Boreus being 

 markedly more so than Panorpa. These genera are the only 

 two that possess a distinctly trunk-like beak. 



The order Mecoptera is commonly characterized as having 

 the head prolonged into a trunk-like beak at the end of which 

 are located the biting mouth-parts. This characterization of 

 the order is inaccurate and somewhat misleading. The term 

 "trunk-like beak" does not fit most of the genera and more- 

 over, the only mouth-parts located at the end of the beak are 

 the mandibles. 



Certain sclerites of the head and mouth-parts are given new 

 interpretations. The portions of the labium which have been 

 regarded as the palpigers by some authors are designated as 

 the mecaglossa, because it is typical of the Mecoptera. It 

 comprises the fused stipulas, palpigers, glossse and paraglossse. 

 The labial palpus is always two-segmented. The two lobes, 

 commonly regarded as a galea and a lacinia, are here considered 

 as subdivisions of the galea. 



The American species of Mecoptera offer no evidence con- 

 firmatory of the opinion of Crampton and Tillyard that the 

 glossae and paraglossae of Peterson in the Diptera are homol- 

 ogous with the labial palpi. 



The normal number of ocelli present is three. They are 

 ordinarily large and subadjacent. The ocelli are wanting in 

 Merope. Authors hitherto have described the ocelli as wanting 

 in Boreus. I have found three small, distant inconspicuous 

 ocelli in this genus. 



BIBLIOGRAPHY. 



Comstock, J, H. and Kochi, C, 1902. The skeleton of the head of insects. Am. 

 Nat., Vol. 36, pp. 13-45; 29 f^gs. 



Crampton, G. C, 1921. The sclerites of the head and mouth-parts of certain 

 immature and adult insects. Ann. Ent. Soc. Am., Vol. 14, pp. 65-103; 

 pis. 2-8. 



Esben-Petersen, P., 1921. Mecoptera. Monographic Revision. Collec. Zool. 

 Selys Longchamps, Fasc. V, pt. 2, pp. 1-172; pis. 1-2. 



