b THE ENTOMOLOGIST. 



imagines in the past admittedly cold season later than in the former 

 years, whereas it is considerably earlier than after the warm 

 summer of 1887, and in the average but little later than in 1880. 

 On the whole such data appear to nie calculated to mislead, an;i 

 should be accepted, if at all, with great caution. 



Field notes are not open to the same objections. Carefully 

 recorded observations of the appearance of many species under 

 their natural conditions should be of considerable value in 

 elucidating the question, and not difficult to obtain from those 

 who are able to make frequent notes in a locality at stated 

 periods. Species that usually occur in considerable numbers 

 should be the best for observation, and comparison between tlie 

 times of appearance of the same species in different localities 

 must not be taken to indicate an earlier or later general emer- 

 gence. I may perha[)s best illustrate my meaning in regard to 

 this suggestion with notes extracted from my diary, of tlie 

 appearance of the second brood of Lyccena hellargus, for the 

 years 1887 and 1888. The first note I have in 1887 is that it 

 Avas taken at an inland locality on August 8th, by a friend with 

 whom I was in frequent communication. At this date I was 

 staying on tlie Sussex coast and daily expecting to meet with the 

 species, but it did not appear until the 28th of the montb. This 

 year I was on the same coast-ground throughout the month of 

 August and until September 12th; a sharp look-out was kept 

 during the whole time, but up to the last date not a specimen 

 was to be seen. It cannot be supposed that the brood was this 

 year completely su[)pressed ; and although the record is in- 

 complete by reason of the species not being found, it appears 

 to be clear that in this one locality it was at least fifteen days 

 later than in 1887, but it would be manifestly unfair to draw a 

 comparison between the inland and coast localities. Insects that 

 have a rapid succession of broods are difficult to deal with, as 

 there is with them the possibility of the end of one brood so 

 overlapping the commencement of another as to render com- 

 parison unti-ustworth}'. 



Mr. Griffiihs's note (Entom. vol. xxi. p. 288) affords me an 

 opportunity of illustrating the difhculty of dealing with suc- 

 cessively-brooded species. Is he right in assuming that the 

 capture of " three fresh specimens " of Tephrosia crejmscularia 

 on July 5th is indicative of a comparatively late emergence ? 

 There is, I beheve, no doubt as to the double-broodedness of this 

 species, the first brood appearing in March and April, the second 

 at the end of June and early in July. Is it not then quite as 

 likely that these specimens should be referred to the second as 

 the first brood ? and in that case their time of appearance would 

 be normal. 



The difficulties in the way of working out so interesting u 



