June 16, 1899.] 



SCIENCE. 



835 



contestable evidence that it was the inten- 

 tion to produce in this something which, 

 with sovereign disdain for all that now ex- 

 ists, was to flow forth from the Eoyal So- 

 ciet}-'s well of wisdom. But the Eoyal 

 Society has not thereby erected a momimen- 

 tum acre perennius, for if the plan should 

 actually be carried out — from which sad 

 result may the good fates spare science — it 

 is unqviestionable that in a very short time 

 the whole scheme, together with numbers 

 and everything else, will have to be changed. 

 However thankfully the news might be re- 

 ceived that a body like the Eoyal Society 

 — to whose esteemed position in the scien- 

 tific world so general a participation in this 

 plan is to be attributed — finds itself im- 

 pelled to continue the plan of a biblio- 

 graphic repertory conceived by the ' Office 

 international bibliographique deBruxelles,' 

 still the question must be raised : Does 

 the uncertain and precarious condition of 

 this undertaking, calculated entirely upon 

 English conditions, warrant the granting of 

 the great cost of its cumbersome organiza- 

 tion from the public means ? 



J. Victor Caeus. 

 Leipzig, Univeksity. 



SOME COMMON SOURCES OF ERROR IN RE- 

 CENT WORK ON COCCW.E. 

 No group of insects has excited more in- 

 terest nor attracted more new students 

 perhaps in the last few years than the 

 scale insects, or Coccidse. Entomological 

 magazines, and, in fact, journals of all sorts 

 and descriptions, and in the most unex- 

 pected and unusual quarters, have been 

 heavily charged with literature of new spe- 

 cies, sub-species, etc. The great number of 

 such new species has struck the attention 

 even of non-workers in this group, and par- 

 ticularly has the designation of an astonish- 

 ing percentage of sub-species, physiological 

 species, varieties, etc., been calculated to 

 arouse the gravest suspicion as to the re- 



liability of the work done and the validity 

 of the forms characterized, especially when 

 the characters on which the new species, 

 sub-species, etc., are based are at all care- 

 fully investigated. That with all the en- 

 thusiasm manifested in working up new 

 material and describing new forms many 

 good species are found and characterized 

 cannot be doubted, and it is, therefore, the 

 more to be regretted that the authors re- 

 sponsible for much good work have been 

 led by a surplus of zeal to be guilty also of 

 much that must be a positive detriment to 

 the knowledge of this group of insects. For 

 the benefit of future students, and with the 

 intention merely to bring about, if possible, 

 a much needed reform in the interest of the 

 scientific value of the work done, it may 

 not be out of place to call attention to some 

 of the common sources of error and ques- 

 tionable work. The criticisms to follow 

 apply more particularly to the scale insects 

 belonging to the Diaspinse, with which the 

 writer is most familiar, and especially to 

 the genus Aspidiotus in its old and broader 

 sense. 



In the first place, it does not seem to 

 have been sufficiently impressed on most 

 writers that the scale covering, though an 

 important adjunct of the insect, is not the 

 insect itself, and still less the extraneous 

 matter, such as sooty mold, epidermis of 

 bark or leaf, etc. , with which the scale may 

 be covered. Many of the Diaspinae — in fact, 

 almost any of them — at times may assume a 

 slight or marked so-called ' mining ' habit. 

 In other words, the female insect in revolv- 

 ing from side to side in the formation of 

 the covering scale, and in making additions 

 to it, is very apt, with her flat chitinous 

 lobes, to cut under the superficial and more 

 or less loosened layers of the bark, with its 

 covering of mold or other extraneous mat- 

 ter, and this loosened material slides up 

 over the scale and adheres closely to it, 

 much modifying and changing its color and 



