44 TUE DURATION OF LIFE. 



instance, been found at this time ' (' Entomolog. Nachrichten,' 

 1881, p. 146). 



In answer to my question as to whether the fact that certain 

 Lepidoptera take no solid or liquid food, and are, in fact, without 

 a functional mouth, may be considered as evidence for an adapta- 

 tion of the length of life to the rapid deposition of eggs, Dr. Speyer 

 replies : ' The wingless females of the Psychidae do not seem to 

 possess a mouth, at any rate I cannot find one in Psyche unicolor 

 (gramineUa). They do not leave the case during life, and certainly 

 do not drink water. The same is true of the wingless female of 

 Heterogynis, and of Orgyia ericae, and probably of all the females of 

 the genus Orgyia ; and as far as I can judge from cabinet specimens, 

 it is probably true of the males of Heterogynis and Psyche. I have 

 never seen the day-flying Saturnidae, Bomlycidae, and other Lepi- 

 doptera with a rudimentary proboscis, settle in damp places, or 

 suck any moist substance, and I doubt if they would ever do this. 

 The sucking apparatus is probably deficient.' 



In answer to my question as to whether the males of any species 

 of butterfly or moth are known to pass a life of different length 

 from that of the female, Dr. Speyer stated that he knew of no ob- 

 servations on this point. 



The following are the only instances of well-established direct 

 observations upon single individuals, in my possession J : 



Pieris napi, var. Iryoniae $ and $ , captured on the wing : lived 

 in confinement ten days, and were then killed. 



Vanessa prorsa lived at most ten days in confinement. 



Vanessa urticae lived ten to thirteen days in confinement. 



Papilio ajax. According to a letter from Mr. "W. H. Edwards, 

 the female, when she leaves the pupa, contains unripe eggs in her 

 body, and lives for about six weeks calculating from the first 

 appearance of this butterfly to the disappearance of the same 

 generation 2 . The males live longer, and continue to fly when very 

 worn and exhausted. A worn female is very seldom seen ; ' I 

 believe the female does not live long after laying her eggs, but 

 this takes some days, and probably two weeks.' 



Lycaena violacea. According to Mr. Edwards, the first brood of 

 this species lives three to four weeks at the most. 



1 When no authority is given, the observations are my own. 



2 In the paper quoted above, Edwards, after weighing all the evidence, reduces 

 the length of life from three to four weeks. 



