NOTICES AND UEVIEWS. 161 



" Food, feeders and fed," but his knowledge of " Englisli caterpillars " 

 which are cannibals is rather mixed, for he states that " Thyatyra 

 derasa, Characlea delphinii and Cosmia trapezina are well-known 

 examples." C. deJphinii is evidently better known as a British insect 

 in America than it is in liritain. Mr. Stevenson gives an account of 

 " An attack of Kpliesiin interpnncteUa " on some raisins imported from 

 Smyrna by Liverjjool and Montreal to London, Ontario. Of " Para- 

 sitism, the balance wheel of nature," Mr. F. M. Webster discourses 

 this year. There is a very mild criticism of some very rash statements 

 on the subject that we ourselves noticed last year in these pages, and 

 we quite agree with Mr. Webster that no one, " be he ever so good an 

 o})server, can, within the space of one life-time, collect sufficient data 

 upon which to base the statement that ' they (i)arasites) usually appear in 

 force only after the damage is done.' " Mr. J. Alston Moffatt furnishes 

 a paper on the re-appearance of Pier in p)rotodice near London, Ontario, 

 in October, 1894. This sjiecies, a close ally of P. rapae, has not been 

 seen since 1872 (before then it had been abundant), the year when 

 P. rapae was introduced into the district. Wherever the introduced 

 P. rapae has spread, from there P. protodice has vanished. The 

 explanations given have usually been rather far-fetched, but Mr. 

 Moffatt's conclusions are worth repeating. He says: — "Now it is 

 generally admitted that the life of Europe is of a more vigorous, 

 tenacious and aggressive character than that indigenous to this 

 continent ; therefore I come to the conclusion that p)i'otodice and rapae 

 are but different races of the one species, and that when they met and 

 commingled, the stronger constitution and proclivities of rapae pre- 

 vailed, and the outcome of the union were all stamped unmistakeably 

 rapae, the characteristics of protodice being completely absorbed and 

 obliterated .... Therefore, when these external influences (which 

 produced the typical p>rotodice and brought it into harmony with its 

 environment at first and which still exist) have had sufficient time 

 to work their utmost upon rapae, and no fresh importations take 

 place, a reversion to the original type will take place as a matter of 

 coui'se." 



Some of our readers may remember an article on " Wing Structure " 

 by Mr. Moffatt that appeared in the second volume of tlie Record 

 (p. 274). In the Report under consideration Mr. Moffatt publishes a 

 fixrther pajDer on the same subject, entitled " Remarks on the structure 

 of the undeveloped wings of the Satnrniidae." This paper is too long 

 to quote in extenso, biit it will be found by all biological lepidopterists 

 to be one of extreme interest. Dealing with the suggestion that the 

 nervures might be constructed spirally, and that the extension of the 

 wing might be jiroduced by, as it were, the relaxing of a compressed 

 spring, Mr. ]\Ioffatt says : — " I could see nothing to confirm such a 

 view. The prominent rings of each segment made a complete circle. 

 The extension of the nervure is in a straight line, something after the 

 manner of the drawing out of a telescope, only the one section not 

 merely draws out of the other, but the small end of the one section 

 draws out with it the inside of the large end, and keeps on extending 

 until the nervure is all brought to a uniform thickness, with a slight 

 reduction at the outer end." He is satisfied that extension is not 

 brought about by the pressiu'e of fluid within the nervures, and gives 

 as his reason that he found tlie nervures of an expanded wing liollow 



