POST-ANTENNAL OEGAN. 67 



malvacees indigenes, entre autres les Malva et les 

 Althcea. Qnelque soin que j'aie mis a clierclier si du 

 point central il naissait un poil allonge ou touts 

 autre production dermique, je dois dire que je n'en ai 

 point trouve." 



Tullberg suggests, though with some doubt, that 

 the so-called eyes of L. fimetaria are in reality homo- 

 logous, not with the eyes of other Collembola, but 

 with the post-antennal organs of L. marithna, 'which, they 

 more nearly resemble both in position and in structure. 

 The so-called " eye " of iv. fimetaria consists of minute, 

 circular, colourless, elevations (PL LVI,fig. 26), arranged 

 in two almost contiguous rows, and which are only visible 

 under a high power and with a good illumination. Simi- 

 lar organs occur in other species of the same genus, as, 

 for instance, in L. Burmeisteri (PI. XLY, fig. 16). In- 

 deed, they will probably be found in all the true Lqnirw. 

 I have always felt a difficulty in regarding this curious 

 structure as an organ of vision, and am disposed to 

 adopt TuUberg's suggestion. 



The eyes are situated behind the antennse, on the 

 upper surface of the head. They consist of distinct 

 ocelli, collected together, however, in two groups, one 

 on each side of the head, and generally situated on a 

 dark patch. The number and arrangement of the 

 ocelli afford good specific and generic characters, 

 though in many cases, from their minute size, the 

 curvature and delicacy of the surface on which they are 

 placed, and the hairs or scales by which they are 

 surrounded, they are not very easy to determine. In 

 most cases the ocelli are approximately equal in size, 

 but in some genera one or more are much smaller than 

 the rest. 



The number and arrangement of the ocelli in the 

 different genera are shown in Pis. LY and LYI. 

 Templetonia has a single ocellus on each side ; Orche- 

 sella has six, arranged in the form of an S ; Tomocerus 

 and Isotorna have seven ; Degeeria, Lejndocyrtus, Smyn- 

 thurus, and Pa/pirius, eight. 



