286 THK kxtomoi.oCtISt's record. 



it may now, I believe, be conceded that generic units have no recognis- 

 able physiological or evolutionary meaning. Generic names bring 

 together species which have so much in common, that it is convenient 

 to think of them habitually in association, leaving their differences to 

 be sufficiently emphasised by the specific names. These groupings 

 have no natural significance definite enoiujli for ijeneral reeoj/nitioyi. It 

 is, therefore, surely best in every case of doubt to maintain, rather than 

 to subdivide, genera, lest we come to have two names where one is 

 enough. 



A considerable section of the book is devoted to a recital of the 

 facts regarding alleged hybrids between the various Kumorphids. Mv. 

 Tutt states that in only one of these instances has it been declared that 

 the actual pairing of the two species {elpenur and jiorreUiis) been 

 observed, and this case he doubts. He is certainly right in insisting 

 on caution before accepting as evidence of hybridisation phenomena 

 which may well be variational. But, after examining the evidence he 

 has collected, I can find no clear reason for deciding, as Mr. Tutt does, 

 at/ainst the hybridisation view. Pending experiment, the nature of 

 these cases should be regarded as simply problematical. I have an 

 impression that Mr. Tutt's bias is here determined partly by his judg- 

 ment on the question of generic subdivision. Nevertheless, the 

 hypothesis that the so-called hybrids are variations connecting the two 

 putative parental forms, somewhat weakens the emphasis laid on the 

 generic distinctions. Moreover, as Mr. Tutt is doubtless well aware, 

 there are many groups, both of animals and plants, in which hybrids 

 occur between types, which all of us agree should be treated as 

 generically distinct. The successful continuation of ^Ir. Tutt's book 

 is so important to entomology, and especially evolutionary science, for 

 which it contains the raw material in plenty, that I trust both he and 

 his collaborators will give earnest consideration to the recommendation 

 made above. Every page unnecessarily included delays the progress of 

 the whole and tends to obscure its high scientific qualities. If a wise 

 course of compression be followed, we may look forward to acquiring, 

 within a reasonable time, a treatise which will be nothing less than 

 corpus of human knowledge respecting the natural history of British 

 lepidoptera. Huch a work will rapidly make itself known, and must 

 infallibly find its way to every scientific library. 



Egg and newly=hatched larva of Brenthis thore ("vYA t(ru fdatcs). 



By T. A. CHAPMAN, M.D., F.Z.S., F.E.S. 



These eggs were sent to me by Mr. Tutt, my notes of them have 

 the date of July 25th, 1903, as that on which they were laid and for- 

 warded by ^Ir. W. H. St. Quintin, to Mr. Tutt. When I received them 

 several eggs were dead and several had hatched, and the young larvie 

 dead and shrivelled up. By exposure to moisture the larval structure 

 as to hairs, etc., became easily examined, and Mr. Tonge made photo- 

 graphs of the eggs and young larvfp. Those of the egg include a 

 notably successful one of the micropylar area of the Qg,g. These are 

 severally reproduced herewith. 



Description of eug. — A tall upright egg, rather thimble-shaped. 

 Height l-08mm. ^^'idth near base 0"7mm., at 0-15mni. from top 

 0-5mm., but midway between these two points it is more than 0-6mm., 



