NO. 1361. REVISION OF AMERICAN SIPJIOXAJ'TERA— BAKER. 427 



forms, and also the groat proljabilit}- of sonic of the European species 

 having been introduced. If these are found anywhere it will he in or 

 near our great ports, and from these localities we ha\e no specimens 

 collected on house mice or rats. 



SYNOPSIS OF AMERICAN SPECIES. 



tt. J k'ad without ctenidial npiiiea (ilpinus (p. 427). 



<i(i. Head with ctenidia. 



I>. Head otenidia of two ypines each hesperomiis (p. 428) . 



hb. Head ctenidia of four spines eacli mexicanus (p. 430). 



CTENOPSYLLUS ALPINUS Baker. 



This species is still known only from the types — a male and female 

 collected b}" Professor Bruner at Georgetown, Colorado, on Ncoioma. 

 It is congeneric with inuscul'i., showing the same peculiar type of head, 

 but it has no genal ctenidia. The following descriptive notes are 

 added: 



Female: Head gently rounded or nearh' flat above from occiput to 

 frontal notch (which is v^ery high on the front), thence sloping down- 

 ward and backward to the mouth. The bristles on the head are 

 developed into short, stout, dark-colored spines, all of which project 

 downward and backward. The antennal groove extends to about two- 

 thirds the depth of the head, and above is connected by a chitinous 

 thickening and furrow across the top of the head with the antennal 

 groove on opposite side. Near the margin of the front on either side, 

 extending from mouth to antennal groove, is a row of ten short, stout 

 s})ines. There are only two spines in the normal lower row on gena. 

 The upper row has six spines, but instead of stopping above at the 

 antennal groove this row^ curves around cephalad nearly to the margin 

 of the front. Disk of vertex on each side witii three oblitpie rows of 

 spines, an upper one of two spines, a middle of three, and a lower one 

 of live spines. The antennal grooAC is somewhat contracted below, 

 and is without minute hairs or bristles on the posterior margin. The 

 labial palpi extend to one-third of the anterior femora. 



Pronotum with a row of about twelve stout bristles on the posterior 

 third, and on the hind margin a ctenidium of about eighteen or twenty 

 spines. The usual soft and minute articulatory hairs on anterior margin 

 of mesonotum are here small teeth. Meso- and metanotum each with 

 a transver.se row of about eight bristles. Metathoracic epi})hysis with 

 about ten irregularl}^ placed bri.stles. 



First al)dominal tergite with three or four small teeth on either side 

 of hind niaroin. The abdominal tergites each has a transverse row 

 of about ten bristles. Antepygidial bristles three on each side, the 

 middle one in each group slightly longer. Abdominal sternites each 

 with a row of about ten rather strt)ng and dose-set bri.stles. The 

 • 'ighth segment, near the middh' of hind margin on cither side, witii a 



