PULEX. 



[ 543 ] 



PULEX. 



a proper peridium, but sm*rounclecl some- 

 times by thickish cylindrical paraphyses, 

 very rarely connected below into a mem- 

 brane, forming a kind of ciliated peridium ; 

 the styluspores are round and mostly spinu- 

 lose, with three or four equidistant pores. 

 The Puccineoiis fruits are also scattered or 

 grouped in circles, sometimes containing 

 only their proper spores, sometimes with 

 Urediuous spores intermixed, destitute of a 

 proper peridium, but, like the Uredines, 

 having sometimes a false envelope formed 

 of confluent paraphyses ; their spores, form- 

 ing the chief distinctive character of the 

 genus, are hilocular, oblong or globose, 

 rounded-obtuse or acuminate at the apex, 

 smooth or spinulose, the upper loculus with 

 a pore at its summit, the lower with a pore 

 at the upper end of one side (next the sep- 

 tum). 



These plants occur commonly on the 

 Grasses and many other herbaceous plants, 

 often changing colour during the summer, 

 being yellow or orange when the Urediuous 

 spores are ripe, and afterwards blackish 

 when the Puccineous form is mature. 



The species are very numerous, but some 

 of those formerly included under this name 

 are now removed to other genera, such as 

 Uromyces, Triphragmium, &c. (See Ure- 

 dines.) P. graminis is common on corn 

 and other grasses (Mildew); among the other 

 frequent species are P. Coricis, p)olygonorum, 

 menthce, anemones, buxi, &c. Ch. Robin de- 

 scribes a Puccinia, apparently on the author- 

 ity of Ardsten, a Swedish physician, found 

 upon the human head in Favus. From 

 his description it appears to be a true Puc- 

 cinia, and should hold its place (P. Favi, 

 Ai-dst.) among the species. But what is 

 more remarkable, it occurs together with 

 Achorion ScJicenleinii, the latter presenting 

 itself as a constituent of the cups or crusts, 

 while the Puccinia occurs afterwards on the 

 desquamations of the epidermis. This ap- 

 pears to warrant (from what we know of the 

 species parasitic on vegetables) the opinion 

 that the Achorion is merely the sperma- 

 gonial form of the P. Favi. 



BiBL. Berk. Brit. Flor. ii. pt. 2. p. 363, 

 Ann. Nat. Hist. vi. p. 439, ibid. 2 ser. v. 

 p. 462, xiii. p. 461 ; Tulasne, Ann. des Sc. 

 nat. 3 ser. vii. p. 12, ihid. 4 ser. ii. p. 77 - 

 138 & 182 ; Leveille, ihid. 3 ser. viii. p. 369; 

 De Bary, Brandpilze, p. 36 ; Fries, Summa 

 Veg. p. 513; Robin, Vegetaux parasit. 2nd 

 ed. p. 613. pi. 14. fig. 13. 



PULEX, Linn. (Flea).— A genus of In- 



sects, of the order Siphonaptera (Suctoria 

 or Aphaniptera), and family Pulicidae. 



Char. As there are only the single family 

 and genus in the order, the characters of the 

 latter are distinctive. 



Head small (PI. 28. fig. 9), compressed, 

 rounded above, truncate in front, in some 

 species with an inferior pectinate fringe of 

 blackish-bro\^^l teeth; eyes one on each 

 side, round, simple, smooth; behind each 

 eye is a cavity or depression, at the bottom 

 of which the antennae are attached; an- 

 tennae (figs, da, 12) four-jointed, their form 

 varjdng in the different species, the third 

 joint very minute, and forming the cup- 

 shaped base of the terminal joint or piece, 

 which in some species is furnished with nu- 

 merous transverse incisions, representing as 

 man)^ distinct joints ; in some the antennae 

 extend out of the depression, and are carried 

 erect. 



Oral appendages (PI. 28. fig. 9 e) composed 

 of several parts : 1. (PI. 26. figs. 32 d, 33 d) 

 The uppermost is single, and consists of a 

 thin, flattened seta, coarsely toothed on the 

 upi^er surface, and traversed throughout its 

 entire length by a canal, upon the walls of 

 which a very slender trachea runs, and from 

 which very minute canals, terminating at the 

 end of the little teeth, are given off. This 

 is the suctorial organ, and perhaps cor- 

 responds to the labrum, but is sometimes 

 considered as the lingua or ligula. 2. (figs. 

 32/, 33/) Two quadrangular, narrow, and 

 elongated plates, each furnished with longi- 

 tudinal ribs, and with fine teeth ; these are 

 the lancets or scalpella, and correspond to 

 the mandibles. 3. (PI. 26. fig. 32^) Two 

 somewhat triangular or leaf-like plates, the 

 maxillae ; to which are attached — 4. (PI. 26. 

 fig. 32 h ; PI. 28. fig. 9 d) Two nearly cylin- 

 drical four-jointed maxillary palpi. 5. (PL 

 26. fig. 32 k ; fig. 33 k) Two labial palpi, in 

 the form of sheaths, fom'-jointed, thickened 

 at the back and membranous at the margin; 

 these palpi arise from near the apex of — 

 6. (PI. 26. fig. 33 I) A small membranous 

 labium, with the still smaller mentum (PL 26, 

 fig. 33 m) at its base. 



Thorax composed of three segments, each 

 consisting of an upper (PL 28, fig. 9 c) and a 

 lower piece (//, that of the metathoracic seg- 

 ment is not lettered) ; from the lower ai'ise 

 the corresponding legs. The two posterior 

 segments of the thorax are each furnished 

 with a pair of plates, the hindermost of which 

 is longest, and nearly covers the sides of the 

 first and part of the second abdominal seg- 



