SCIENCE-GOSSIP. 



the dew was settling. I could only "bottle'' 

 one in a specimen tube, because when I tried in 



get another tin 1 first escaped. The scales are very 

 thin and transparent, the markings very delicate 

 and tine, and the "exclamation marks" in differenl 

 rows seem as a rule to alternate more than in the 

 preceding species (see fig. 4). It is the exceeding 

 tenuity of the scales which makes me refer the 

 insect to the present species (see Lubbock, p. '!'>.'<). 

 'The scale would probably be a good test oojecl if 

 difficulty of exhibiting the markings were the only 

 qualification. Seira bltsltii (fig. 5) may give some 

 idea of these scales. They are of leal-like shape. 

 and have a very small number of exceptionally 

 large " exclamation marks " ; altogether they look 



Fig. 9. Lepidoayrtus curvicollis. 



as if they might be a primordial or ancestral 

 type of Podura scale. They might be studied 

 with advantage as throwing light on the struc- 

 ture of the scales of other Collembola, the 

 marks, though few in number, being so vastly 

 larger than those of any other species. I found 

 the insect on ivy on a wall by the railway at Shep- 

 reth, Cainbs, in June 1886. Tomocerus plumbeus or 

 jtfacrotoma plvmibea is a small, almost black insect, 

 of which I found a solitary specimen under a stone 

 in the woods at Colwyn Bay. This was almost the 

 first stone I examined, and although I looked under 

 many others I could not find any. This is an exceed- 

 ingly pretty scale, quite different from those of the 

 other Collembola, and approaching more nearly to 

 those of the Thysanura, Machilis and Lepisnta. 

 It has no " note of exclamation," but instead has 

 regular longitudinal striae, and between them faint 

 transverse striae as in Machilis (see fig. 11), and 



Fig. 10. Test-scale of L. curvicollis faintly marked, showing 

 watered-silk appearance under low power. 



also several radiating corrugations starting from 

 the pedicle corresponding to those of Lepisma. It 

 thus combines two different types of structure. Its 

 dark colour also helps to render it a beautiful object. 

 Machilis maritima (cf. fig. 11) is an insect about 

 half an inch long, brown with pretty inottlings 

 and white rings on the three long bristles, from 

 which it receives the name of "bristle-tail." It 

 was simply swarming on rocks just above high- 

 water mark outside the month of the Dart, in 

 South Devon, on the Kingswear side, but was very 

 difficult to catch and bottle. I got three after 

 trying for a long time. 1 have also seen it in 

 abundance on the rocks by the shore at Lynmouth. 

 in North Devon. The scales are to my mind 

 prettier than those of Lepisma on account of the 



regularity of their transverse striae, which are 



absenl from the latter. On the other hand, this 



one has qoI the radiating marks of Lepisnta, though 



both structures occur Ln Tomocerus. Lepisnta 



saccharina ( fig.- L2), This it secf 



down on the slide instead of the cover (- >. and the 



scales have thai side uppermosl which was 



the body. In another slide the scales wi • 



down on the cover, and so the uppermosl side is 



11. Scale of Machili 



jii ■Itipoda. 



Scale of Lepisma 

 accharina. 



the outermost, when the scales were on the insect 

 It will be seen that the longitudinal marks are on 

 the outer side, and the radial ones on the side next 

 the body, the appearance presented being roughly 

 sketched in tigs. 6 and 7 ( J ). Of course, the mark- 

 ings which are uppermost appear continuous, and 

 these are the longitudinal marks in fig. 7. win-li- 

 the outer surface has been pressed against t he- 

 cover. The presence of a little grease on the slide 

 represented by fig. 8 also serves to point to the 



Fig. 13. Scales of Polyommatus argus, snowing interference 

 strata. 



same conclusion. In a few scales this grease 

 causes the scale to adhere to the cover, thus 

 obliterating the longitudinal marks on the upper 

 side, and the radiating striae on the under side will 

 then be seen to be perfectly continuous and far bi 

 shown than in any other part of the scali 

 fig. 8). Where only a very little grease is present, 



(2 i The scales are transferred to a slip of glass, generally the 

 [•-glass, by simply pressing it gently mi the bodj ol the 

 insect.— Ed. Microscopj . 



(3) Mr. Joseph Beck, in his appendix to sir John Lnbl 

 i' Monograph of the Collembola and Thysanura," states tlmr 

 the longitudinal markings arc on the under side of the scale, 



