( x ci ) 



development, in conformity with the general law adverted to, 

 being, as a rule, rapid in the warm season, slow or even 

 arrested during the colder part of the year. 



Year-lived Lepidoptera. 



The more usual case, at least in our latitudes, may be taken 

 to be that of insects which live a whole year, constituting those 

 seasonal species which are usually called single-brooded, but which 

 it might be more convenient, as their whole life is in question 

 and the term "brood" is often used in a different sense, to 

 call " year-lived." These, in contrast with the non-seasonal 

 species, are in general, in their four several stages — those of 

 egg, larva, pupa, and imago — associated respectively with 

 particular seasons of the year, and any of their stages, varying 

 however according to species, may be associated with any 

 season. 



It will be convenient here, as the foundation for some of 

 the observations that follow, to refer to a few familiar 

 examples of the extreme, persistence in their habits, in disregard, 

 apparently, of very great differences of temperature, of some 

 of the " year-lived " class, so numerous in temperate countries, 

 and to select for that purpose some that pass the winter in 

 varying stages. Euchlo'e cardamines ranges over Europe and 

 a large part of Asia, and is found plentifully at low elevations 

 as well as up to 7,000 feet above the sea level. Appearing 

 on the Eiviera in February or March, and in the mountain 

 districts found occasionally as late as August, it pupates usually 

 in the early part of summer and then (with rare exceptions, if 

 any) quietly bides its time through all the hottest part of a 

 South European summer until the spring of the following 

 year. This is an insect which has a winter pupa. The 

 same rigid adherence to the one-year cycle is shown generally 

 by the Erebias and other Satyrids, chiefly mountain insects, 

 but many of them found in the warmer plains ; these pass 

 the winter in the larval stage, as does Aporia cratsegi, a 

 very abundant species with wide geographical range. A 

 similar fixed yearly life is shown by species which, like 

 Argynnis adippe, Augiades comma, Lyceena segon (argus), the 



