NOTES AND OBSERVATIONS. 17 



4. Any facts connected with a species which the sender thinks 

 important and suitable for a " Keport " should be communicated on a 

 separate sheet of paper, written on one side onli/ the notes on each 

 species should be dated and signed by the writer. A Report will be 

 issued at the close of each year containing the various notes sent in 

 by contributors. 



5. Each parcel should be accompanied by a list of insects the 

 member wishes to receive from the Club. This list is to be made by 

 drawing a short horizontal line before their names in the catalogue. 

 Species especially wished for should have a ! before the horizontal 

 line. The name of the member and address to which the return 

 parcel is to be sent should be written on the outside of the catalogue, 

 together with any special directions as to the route by which it should 

 be forwarded ; the yearly change of distributors necessitates clearness 

 in this particular. When the same copy of the catalogue is used more 

 than once, the species which are no longer wanted, but which were 

 marked, should have a perpendicular line drawn through the horizontal 

 line. Manuscript lists will not be received. 



6. Parcels should be sent by parcels post, or by any other means, 

 carriage paid, to one of the distributors for the year not later than the 

 31st December. Those arriving after that date will not be available for 

 the ensuing distribution. Members who send the more valuable 

 parcels will have their return parcels selected before those who send 

 inferior ones. — W. J. Kaye (Sec. City Lond. Ent. Soc). 



Insect Periodicity; Maximum and Minimum Periods. — With re- 

 ference to the discussion concerning Plusia moneta which has been 

 going on in these pages (Lawrance, vol. xxxv. p. 242 ; Colthrup, ibid. 

 p. 320), I should like to point out that it is dangerous to generalize 

 too widely from imperfect data. In some cases no doubt the sudden 

 appearance of a species in large numbers (F. antiopa), or the addition 

 of a new species to our fauna ( P. moneta) may be due to immigration 

 or importation. But it does not follow that all increases towards the 

 maximum are to be explained in a similar way. Allowance must be 

 made for secular causes, such as climatic influence upon the special 

 enemies of the species, and so forth. It is difficult, and in most cases 

 practically impossible, to surmise what local fluctuation in external 

 conditions has been operative in determining the maximum or mini- 

 mum appearance of a species, but it does not seem to me necessary to 

 invoke the factor of Continental supply whenever we are unable to 

 explain the abundance of a particular insect. These thoughts have 

 been called forth by Mr. Colthrup's remarks {loc. cit.) concerning 

 Porthesia clinjsorrluea. All that can be said is that we have had a 

 " good year " for this species both here and on the Continent. My 

 reason for ofleriug this contribution to the discussion is that I noted 

 the abundance of this insect this autumn in North Wales, all along 

 the coast from Colwyn Bay to Peumaenmawr, and inland about Capel 

 Curig. There is no direct Continental communication with this coast. 

 —(Prof.) R. Meldola; 6, Brunswick Square, W.C, Dec. 6th, 1902. 



'•Emperor of Morocco." — This has been used as the name of a 

 butterfly ; but I am only acquainted with the two instances quoted in 



ENTOM. — JANUARY, 1903. C 



