184 THE CANADIAN FNTOINIOLOGIST 



ON CHILOPODS OF THE FAMILY IMFCISTOCEPHALID^. 



BY r<Al-ni V. rHAMBF:KLlN, 



Cambridge, Mass 



While some contusion still exists in the application of the generic 

 name Mecislocephalus Newport and consecpienth- of the family name 

 Mecistocephalida^, inuler the rules of the International Code the problem is a 

 simple one, and punctifrons Newport is clearly the type of the genus. i>amnonyx 

 thus falls as a synonym to Mecistocephalus. In the present paper Mecisto- 

 cephalus is regarded as thus unalterably fixed, and the famib- Mecistoccphalidie 

 is treated broadly as including all mecistocephaloid lorms 



Key to (iENKRA OF Till': M)':( isToi-iiAi.iD.i':. 

 a. Coxosterna of second maxilUe discrete, not fused at middle line; palpi 



of second maxilhr clawless (Arrupina^). 



b. Coxa' of first maxilla' discrete Arrup Chamberlin. 



1)1). Coxce of first maxilla- fused Prolanuionyx vSiKestri. 



aa. Coxosterna of second maxilke united at middle line; palpi of second maxilhe 



with claws ( Mecistocephalincc) . 



b. Cephalic plate with a stout spine beneath near each anterolateral 

 corner; clypeal region divided by a distinctly areolate median longi- 

 tudinal band extending from anterior areolate area; clypeal seta- few. 

 c. Coxopleurie of last pediferous segment xery large, extending to 

 or l)eyond the spiracle of the preceding 



segment Megelhmus Cook. 



cc. Coxopleurie of last pediferous segment of normal size, not 

 embracing the preceding segment, 

 d. Laminae of mandibles, excepting the first, with teeth con- 

 fined to distal region proximad of where they are replaced 

 by a close line of cilia. 

 Lateral pieces of labrum with margin ciliate through- 



ou t I )asy pt yx Chamberli n . 



dd. Laminar of mandibles with teeth throughout, no such 

 ciliate lines, 

 e. Labral margins shortly ciliate throughout; teeth ol 

 mandibular lamina?, except distally, exceedingly 



minute Brachyptyx, gen. nov.* 



ee. Labral margins either wholly smooth or setose or 



ciliate only for a very short distance subjacent to 



median angles; proximal teeth of mandibular lamina' 



not at all or only moderately and gradually reducx'd. 



f. Labral margins wholly smooth; teeth of first 



lamina of mandibles seven or 



less Mecistocephalus Newport . 



ff. Labral free margins with a tew seta' or a short 

 line of cilia at mesal ends subjacent to median 

 piece; teeth of first mandibular lamina teji or 

 more, the n.esal edge of mandible 

 serrate Pauroptyx, gen . nov. 



*G8notvpe, Mecistocephalus wirandus Pnrork (Lanmonvx wirandus Silvcstri). 

 August, 1920. 



