limn, MICROSCOPICAL .7 0UIINAL. 3 



scales are still worthy of attention. About the time of 

 their popularity Sir John Lubbock wrote a "Monograph 

 of the Collembola and Thysanura," published by the Ray 

 Society in 1872, and in the same year Mr. S.J. Mclntyre 

 contributed a paper on them to Science-Gossip for Decem- 

 ber 1872 and January 1873. Sir. J. Lubbock's book con- 

 tains a valuable appendix on the scales of these insects 

 by Joseph Beck, illustrated by fine lithographic plates 

 from drawings by his brother, the late Richard Beck. 

 Lepidocyrtus curvicollis. — Scales of this insect are often 

 seen in old collections labelled "Podura plumbea," al- 

 though the generic name Podura is now given to an in- 

 sect without scales, aud plumbea is the specific name of 

 almost the only one of the Collembola whose scales do not 

 show the familiar "marks of exclamation." This is one 

 of the largest species of the genus, and when alive looks 

 darkish. This slide is best examined without the cover on, 

 for which purpose the central part of the ornamental paper 

 is not gummed down. To remove the cover, carefully in- 

 sert a slip of thin card or note-paper under the edge of 

 the green paper at one side and push the cover out at the 

 other ; replace in the same way when done with. If the 

 cover breaks, a fresh one can be inserted. This is really 

 an excellent device for mounting dry objects, and is worth 

 remembering. Note the saltatory appendage from which 

 the name "springtail" is derived; also the curious hump- 

 back projection of the thorax characteristic of the genus 

 Lepidocyrtus, from which the specific name curvicollis is 

 derived. L. curvicollis seems to have two varieties charac- 

 terized by difference in their scales, which are called "or- 

 dinary" and "test" scales. [Students of these scales can 

 purchase them at the opticians, but they are unfortunate- 

 ly becoming increasingly difficult to procure. A slide of 

 the "test" Podura only should be asked for, mounted dry. 

 Under the microscope the coarser scales and those actually 

 in contact with the cover-glass, should be examined. In 



