SCIENCE-GOSSIP. 



281 



jiuviaiilis are considered as being doubly used if 

 employed in the same genus. 



Clans; 53. — It is very desirable that every 

 original description of a new genus or a new species 

 should be accompanied by a Latin diagnosis, 

 at once individual and differential ; or, at least, a 

 diagnosis in one of the four European languages 

 best distributed (English, German, French, Italian). 

 - : .-' 54. — In works which are not published in 

 any of these four languages, it is very desirable 

 that the explanations of the figures and plates 

 should be wholly translated into Latin or into any 

 of these languages. 



Clause 55. — Words are to be avoided which are 

 only distinguished by a masculine, feminine, or 

 neuter termination, or only by a slight change of 

 orthography. 



Collateral Questions. 

 Claust 56. — The metric system only is employed 

 in zoology for valuation of the measures. The 

 foot, inch, pound, ounce, etc., ought to be rigor- 

 ously banished from scientific language. 



Clause 57. — Altitudes, depths, speed and all 

 general measures should be expressed in metres. 

 Fathoms, knots, marine miles, etc., ought to 

 disappear from scientific language. 



Clause 5S. — The thousandth of the millimetre 

 (o mm -ooi), represented by the Greek letter ,u, is 

 the unit of measure adopted in micrography. 



Clause 59. — Temperatures are expressed in 

 degrees of the centigrade thermometer of Celsius. 



Clause 60. — Indication of enlargement or of reduc- 

 tion is indispensable for the proper understanding 

 of a drawing. It is expressed in cyphers, and not 

 by mentioning the number of the lens by the aid 

 of which the image was obtained. 



Clause 61. — It is useful to indicate if there is a 

 lineal enlargement or an increase in the surface. 

 This can be easily abridged. Ex., x 50 times a 

 means an increased bulk of 50 times on the sur- 

 face ; x 50 times — indicates a lineal increase of 

 50 times. 



Then follow the rules for the writing of geo- 

 graphical and proper names which were adopted 

 by the International Congress of Zoology. 



HOW FLOWERS ATTRACT INSECTS. 

 By G. W. Bulman. 



TT was Sprengel, Rector of Spandau, near Berlin, 

 a botanist so enthusiastic as to neglect his 

 duties as Pastor, and consequently to lose his post, 

 who first directed attention to the fertilization of 

 flowers by insects, and to the wonderful way in 

 which the former are adapted to the visits of the 

 After undergoing a period of neglect, the 

 idea was taken up and given a fresh development 

 by Darwin and his followers ; but in a different way. 

 By far the most exhaustive series of experiments 

 which have ever been carried out on this subject 

 are those of Professor Plateau, of the University 

 of Ghent These point irresistibly to the other pos- 

 sibility. It is, I believe, beyond dispute that these 

 experiments show that insects are not attracted to 

 • . by their gay colours. An account of these 

 very interesting observations, under the title of 

 "Comment les Fleurs attirent les Insectes," has 

 appeared from time to lime in the " Bulletins de 

 lAca-: ile dc Belgique." I propose to 



riefly an outline of them. 

 I the gaily-coloured flowers of 

 single dahlias with green leaves, in some ca 

 outer ray florets only, in others the whole flower, 

 v,x Plateau four.d that insects visited them 

 as freely a* before Such a result, so much at 

 variance with the generally r> ■ w that 



• are attracted to flowers by their gay colours, 

 seemed to demand further investigation 

 ies*or Plateau set himself by a scries of experiment • 



and observations exhaustively to cross-question 

 nature on the subject. The final answer has been 

 a confirmation of the conclusion pointed to in 

 the first experiments, viz., that colour plays a very 

 subordinate part in attracting insects to flowers. 



The first question put was, " If the gaily- 

 coloured part of a flower be removed, leaving 

 only the green calyx and the honey-bearing parts, 

 will insects still visit it?" To put this question, 

 Professor Plateau took two pots of lobelia, each 

 with thirty or forty flowers, and carefully cut oft 

 with a pair of scissors all the blue corollas in the 

 one pot, leaving those in the other intact. These 

 pots were placed near together in a sunny situation 

 much frequented by insects. Watching them 

 carefully, thirty-three visits to the blue flowers 

 and twenty-five to the green calyces were counted. 

 When Darwin put the question with the same 

 flower he got an opposite answer. For having 

 deprived some lobelia flowers of their blue corollas 

 be found that the bees ceased to visit them. 



Professor Plateau continued his questions with 

 other flowers. He cut off the large, conspicuous 

 ;>:llow corollas of the evening primrose. One bee 

 was seen to visit fourteen of these mutilated flowers 

 in succession n one bee visited 



ten, anotlirr three i ilicr fifteen of these 



Imll ults were 



with iii<- flowers of Convolvulus major, 



lari raflowet and foxglove. When, how- 



