432 MR. LUBBOCK ON THE THYSANURA. 



Length ^tli of an inch. 



Common in Kent, under logs which have been felled and left lying among long 

 grass and underwood. 



I take this opportunity of expressing my thanks to my two neighbours, Messrs. 

 Janson and Solly, who have not only allowed me free access to their woods, but have 

 also arranged logs of wood to serve as protection to the Smynthuridse. These facilities 

 have enabled me to obtain plenty of specimens, and have saved me a great deal of time. 



They feed principally on the spores and fixst shoots of Fungi. Many specimens were 

 infested by a small mite, which adhered to the underside of the body, and was sometimes 

 present in considerable numbers. 



The hairs, which cover the head as well as the body, stand at a distance of about 

 •0047' from one another. They are gently curved, about -0075" in length, and 

 roughened with small asperities or projections. The larger hairs on the antennse are of 

 the same size and structure, while those on the legs are smoother. 



The eyes, as in all the species of the genus, are eight in number on each side. The 

 anterior five are arranged in a quincunx, which is not quite regular, however, one of the 

 posterior pair being a little too far back ; the other three form a triangle. This arrange- 

 ment agrees with that figured by M. Nicolet as characteristic of the genus {I. c. pi. ii. 

 fig. 26) ; but in the present species the eyes are nearer together than in his figure, and 

 agree indeed even more closely with his representation of those of Cyphodeirus {I. c. pi. ii. 

 fig. 22), especially as in that genus he makes the eyes pretty uniform in size, whereas in 

 Smynthurus he represents the central eye of the quincunx as much smaller than the 

 others, which is not the case in this species. 



The antennae are -0475" in length, of which the terminal (so-called) many-jointed 

 portion forms nearly one-half. The basal segment is cylindrical and quite short, being 

 •004" in breadth, and only •OOS" in length. The two following segments are of 

 nearly equal size, being each about •012" in length and -002" in breadth. On 

 the whole they are cylindrical ; but their outline, and especially that of the third, is 

 somewhat knobby. They bear a few scattered bristles, resembling those on the head and 

 body, and also a few smaller hairs near their apices. The terminal portion of the antenna 

 resembles a necklace of beads welded together, and gradually diminishes in size at the 

 tip, though, for the greater part of its length, it has a diameter across the beads of 

 •0015". At each projection is a whorl of small hairs, and at the apex are a few rod-like 

 hairs, resembling those found on the autennee of so many Insects and Crustacea, and 

 which are doubtless organs of sensation, though I was unable, from their minute size, 

 to ascertain their structure in a satisfactory manner. 



The descriptions given by different naturalists of the mouth-parts of these animals have 

 been very dissimilar. Pabricius mentions mandibles and maxillae, labium and two 

 pairs of palpi, consisting respectively of five and three segments. Latreille does not 

 hesitate to characterize this description as being " absolument fictive." Assuredly it is 

 absolutely incorrect ; but is it not more probable that Fabricius should have mistaken the 

 species he examined, than that this great naturalist should have voluntarily committed 

 a fault so certain of detection ? 



I 



