92 



PROF. A. D. IMMS ON 



Genus Heteromuricus, gen, nov. 



Mesonohtm non prominens. Segmentum abdominale quartum 

 quam tertium paullo longius. Antennce quinque articulos habent. 

 Ocelli 16 : 8 m utroque latere capitis. Organa 2>ostantennaMa 

 carent. Segmentimi abdominale qumtumi medio cerco instructum. 

 Cutis squamosa. 



The presence of a single median cercus to the fifth abdominal 

 segment separates this genus from other known genera of 

 Collembola. In possessing five-jointed antennae, and in the body 

 being scaled, it shows perhaps closer relations with Heteromtirm 

 Wankel than with any other genus. 



* Heteromuricus cercifer, sp. n. (PI. VIII. figs. 49-51 \. 

 PI. IX. figs. 52-54.) 



Antennarum articulus quartus longissimus, quain tertius dtiplo 

 longior. Cerctis segmento abdominali tertio longiiudine ceqtialis. 

 Ungitictdus superior duobus minutis dentibus armatus ; ungidcidus 

 injerior lanceolatus, acuminatus , inermis. Alttcrones dentibus 

 duobus atque seta spiniforme iina instracti. Long. 2 mm,. 



Head. — Inclined at a.n angle of 45° with the long axis of the 

 body ; invested with scales and scattered sette. The ej/es eight in 

 number on each side ; post-antennal organs wanting. 



Antennce. — Equal in length to the f urcula ; five-jointed (fig. 52), 

 the joints respectively related in length as 1 : 10 : 12 : 25 : 14. 

 The basal joint small and annular, provided with a whorl of 

 short spine-like setas ; the second and third joints scaled ; the 

 fourth and fifth joints clothed with closely-set -whorls of short, 

 curved hairs. 



Trunk. — Densely clothed with scales (figs. 51 and 52) ; the 

 scales at the hinder extremity of the body, surrounding the base 

 of the cercus, larger than those found elsewhere. The segments 

 nuitually related in length as 6: 6:5:6:8:12:4:1. Arising 

 from the dorsal aspect of the fifth abdominal segment is a 

 prominent median cercus (figs. 50 and 52) nearly equal in length 

 to the third abdominal segment. The cercus densely clothed with 

 scales, and provided ventrally with long slendei- setae, possibly 

 sensory. Along the anterior border of the mesothorax is a 

 " collar " or " frill " of stout setae, and a tuft of similar setae at 

 the extremity of the abdomen. 



Legs. — Sub-equal ; the two basal joints clothed with setae, the 

 remaining joints scaled down to the claws ; interspersed among 

 the scales are numerous hairs and setae (fig. 49). The superior 

 claws of the feet with two small teeth along the inner margin 

 (in five specimens one or other of the teeth were absent). The 

 inferior claios large, lanceolate and acuminate, unarmed ; those of 

 the third pair of legs a little longer than the corresponding claws 

 of the preceding pairs. 



Furcula. — Slender, reaching forwards to the ventral tube ; 

 densely clothed venti'ally with scales. The denies related in 



