312 THE entomologist's record. 



summer larvfe, and a fair number of autumnal imagines, progeny of 

 these spring parents, was recorded. This year, 1904, the spring im- 

 migrants appear to have been fairl}- numerous, and a few autumnal 

 examples resulting therefrom have been captured and bred. We have 

 already localised the probable area whence our central European im- 

 migrants set forth, and this is well supported by facts that have come 

 to hand quite recently. 



In the Uerue de Viticulture, 1904, p. 672, and the Rereil cuiricnle, 1904, 

 p. 404, Mares and Bedos give details of the swarms of this species that 

 occurred in Algeria last spring (1904), the facts of which appear to be 

 as follows : Owing to a very wet winter and spring the earliest 

 imagines of Phri/.vus livornica did not appear till the middle and end of 

 April, when they were driven from the higher lands by the sirocco into 

 the lower cultivated areas. They laid their eggs on the vine, and in 

 the neighbourhood of Ain-Bessem, Bir-Rabalon, Bertuille, Les 

 Trembles, Medea, Loverdo. Gouraya, Berrouaghia, Ben Chicao, 

 Hammam-Rhira, Marguerite, Sidi-Bel-Abbes, &c., the larvae were in 

 enormous numbers, and soon devastated the vineyards, stripping the 

 vines of buds, leaves, and blossoms. Mares states that some children 

 collected from 10-12 litres of larvae in a day, and that after this the 

 larv* seemed as abundant as ever. Their polyphagous habits stood 

 the larvae in good stead, and, in due course, they pupated, and the 

 imagines appeared at the end of July. In Tunis, where the spe3ies 

 has loeen equally abundant this year, the larvae have attacked the olives- 

 in preference to the vines. 



One suspects that the movement in the spring, in Algeria and 

 Tunis, from a higher to a lower level, was part of a large general 

 dispersal movement, the most northerly edge of which touched our 

 coasts. If this were so, it follows that our spring captures were full- 

 blooded North African individuals, and our autumnal ones British-bred, 

 and born from African parents. It is interesting to know that, owing 

 to the greater interest now taken in the question of the distribution of 

 our lepidoptera, we may get from current entomological literature facts- 

 that, pieced together, show us the origin and extent of migration 

 movements in the Palaearctic lepidoptera. 



The numerical relationship of the sexes in Lepidoptera. 



By T. A. CHAPMAN, M.D. 

 Mr. Tutt's luminous analysis of the records of breeding lepidoptera 

 given by Htandfuss (FJnt. Rec, xvi., 193) is abundantly sufficient tO' 

 give its quietus to the thoughtless generalisations founded on superficial 

 and collecting-box observations, which one so frequently sees, and 

 which, as the thoughtless are a majority, we shall continue to see, in 

 periodicals and elsewhere from time to time. In reading it, several 

 ideas occurred to me, as probably they would to most people, one or 

 two of these are possibly worth noting. The first, perhaps, is that the 

 records refer for the most part to more or less ordinary species (in this 

 respect) and to normal breeding of them, and that the conclusions- 

 reached are not in any way invalidated by the fact that there are excep- 

 tional species, of which the most notable are those that are partheno- 

 genetic, or are approaching that habit. There are also exceptional 

 conditions, of which we know little, as in certain hybrids and certain 

 strains occasionally met with in ordinary species. 



