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1. Ceratophyllus penicilliger Gnibe (1852). 



6c?r?, 7 ? ?; July 12 and 31, and Angnst 2 and 3, oS Microtus agiestis. 



1 ? ; July 12, oft" Hi/pudaeus ylareoliis. 



Not previously recorded from Hungary. 



The specimens agree with the insect identified by Wagner as yemciUUjer. 



C. pedias Roths., Ann. Sci. Nat. p. 231. no. 21 (1910), based on a single S from 

 Finland, is close to penicilliger, but differs in the ninth abdominal sternite of tiie 

 (? bearing only thin hairs proximally to the sinns of the horizontal arm, while 

 in penicilliyer there is a short spine among the hairs. 



2. Ceratophyllus sciurorum Sehrank (1803). 



1 ? ; July 8, off Microtus agi-estis. 



The occurrence on this host is certainly accidental. The presence of squirrels 

 in the woods was testified by the fir-cones on which they had been at work. 



3. Ctenophthalmus agyrtes eurous subsp. nov. 



Ti/plilo/i.-ii/lla ,ir,,jrl,'^ (Heller), Wagner, //.»■. S„r. Ent. !l„..<.-<. xxxi. p. 589, tab. 9, fig. 23 (1898). 



3 cJcJ, 11 ? ?; July 8, 11, 12, 21, and August 2 and 31, off Microtus agrestis. 

 6 (?<?, 3? ?; July 12 and August 3, off Ili/pudaeus glareolus. 



2 c?(5', 2 ? ? ; July 11 and 18, off Mus silcaticus. 



1 J, 2 ? ? ; July 31 and August 2 and 3, off Sorex araneus. 



This is a j)articnlarly interesting form of agi/rtes, inasmnch as it goes far to 

 prove that aqi/rtcs Heller (189G) and protincialis Roths. (1910), and presumably 

 also baetici.is Roths. (1910), are geographical races of one widely distributed species. 

 This species appears to respond more readily to differences in its surroundings 

 than any other European flea. The specimens wliich we have examined from a 

 number of countries confirm Dr. A. Dampfs view, expressed to us //; lift., that 

 C. agyrti's would be a profitable subject for tlie study of the geograpliical variation 

 of the clasping organs. 



The Hungarian examples before us agree very well in the c?-genitalia with 

 the figure given by J. Wagner of a Russian specimen, and differ markedly from 

 the figure we published of true aggrfi's in Noe. ZooL 1898, tab. 15a, fig. 1, and 

 tab. 17, fig. 12. Wagner and others attributed the differences in the figures to 

 incorrectness of our drawings. Although our figures were not so good as one 

 might have wished them to be, still the most conspicuous characteristics of 

 true agi/rtes are nevertheless well brought out in them. 



From the specimens we have examined true aggrtrs appears to occur, rougliiy 

 speaking, only west of the Elbe, and the present new geographical race in the 

 countries east of the Elbe. We believe that we can distinguish several more 

 (undescribed) geographical forms. We are, however, not yet in a position to 

 elucidate the question satisfactorily. C. agijrtes eurous is, from the point of 

 view of the clasping organs of the (J, intermediate between C. aggrtes aggrtes 

 and C. promncialis ; and, in the ?, closely approaches y^z-ot-iw/a^/i* in the shape 

 of the seventh abdominal sternite. 



6. The eighth abdominal sternite bears a row of three instead of four bristles, 

 besides a number of bristles more proximally j)laced. The clasper (text-fig. 1) is 

 divided, as in C agyrtes agyrtes, into a long and conical upper process (P') and shorter 

 and broader lower jirocess (P^). This second process is again divided into a conical 



