THE VARIOUS MODES OF EMERGENCE. 67 



the extensive knowledge of Central Italy, which Signor Querci has 

 acquired in many years of collecting, and to my own personal experi- 

 ence, have allowed me to establish in a sufficiently exact manner, the 

 various modes of emergence of the Rhopalocera, and have led me with 

 regard to various species to unexpected conclusions, which seem to me 

 not devoid of interest. 



Northern Tuscany is a country well suited to show the maximum 

 number of broods, which each species is apt to produce, because it lies 

 on the boundary between the climate of Central Europe, where the 

 season favourable for the development of Lepidoptera is limited by 

 the greater duration of the cold, and that of the far south of Europe, 

 where the heat and drought hinder their emergence for a more or less 

 prolonged ' period during summer. It also offers, by reason of its 

 intermediate position, the advantage of a variegated fauna, including 

 the greater part of the European species of both hill and plain. I 

 exclude for the present the single-brooded Tuscan Lepidoptera belong- 

 ing to the higher mountains, which will be better placed in a special 

 work on emergence in relation to altitude. The former in the mean- 

 time also prove to us that the emergence of the various species in the 

 plain is much less variable than was thought, and that these can be 

 gathered in a few groups, each of which behaves according to simple 

 and fixed laws ; bearing which in mind one can easily determine their 

 mode of behaviour in each locality, even with only a few facts to go 

 upon. 



The causes of error, owing to which there have been hitherto so 

 many fantastic theories on the numbers of the broods, are chiefly the 

 two following : — 



The first through not making a clear distinction between the 

 period of emergence, or the true duration of the generation, and the 

 period following, during which individuals, more or less old, continue 

 to show themselves, but during which no more emerge. This last is 

 very variable according to the longevity of each species ; some have a 

 short life and disappear soon after the close of the first period, while 

 others have a very long life ; therefore the second period may be pro- 

 longed till the beginning of a new brood. The importance of this 

 distinction is shown by the following example : Prof. Stefanelli says 

 that Nisnniades tages, L.. is found in Florence from May to September 

 in fact, old individuals, with the wings almost entirely laid bare of 

 scales, are seen till the end of September, but the periods of emergence 

 are two only, and the second one is comparatively very short ; the 

 first brood emerges from April till July and the late individuals of the 

 second partial brood emerge before the 20th of August ; Tutt has been 

 misled for want of this observation by the entomologists of our 

 country, and from the data of Stefanelli and other authors he con- 

 cludes that the ta{/es of southern Europe may have a third brood in 

 September. The Rhopalocera with a longer life are the Vanessidi, 

 which emerge in September and lay their eggs in April, and the 

 Gvnepteryx, chiefly, if not entirely, of male sex, which winter also at 

 the imago stage [imagines kibernantes). 



The female of Satyr us circe is also very long-lived, and presents a 

 phenomenon worthy of note, which, to my knowledge, has not yet 

 been made known ; the males in Florence emerge at the end of June, 

 and disappear altogether soon after ; the females emerge during the 



