OM THE LIFE DURATIO^T OF TfTE HETEROCERA. 341 



sume that the individuals of a species continue to emerge from the pupa during 

 one-third of the above period, there will remain, as the approximate life duration 

 of these Noctuidoi, a jicriod of three weeks. 



Mr. Wm. L. Devereaux, of Clyde, N. Y., in giving the results of his collections 

 of NoctuidcB at sugar for two years,* states that '' most of the species remain for 

 about a month." From other data which I have consulted, I think that we shall 

 not be far from the truth if we adopt as the life-period of the larger portion of 

 the Noctuidce a term of three weeks. 



As might be expected in so heterogeneous a family as the Noctuidm — differ- 

 ing so greatly in general character, coming forth at such diff'erent seasons of the 

 year, and varying in the number of the broods, — the life-histories of the several 

 groups vary to the extent of preventing generalization and necessitating specific 

 observations. For example, we find that the genera Xylina, Jlomoptet'a, and 

 Catocala have their periods of apparition much extended beyond the species 

 above noticed. In the paper by myself, above referred to (p. 51), we find that 

 Xylina petulca, X. disposita and X Bethunei were observed for a period extend- 

 ing over forty-one, forty-seven and fifty-one days respectively, with a possible 

 prolongation of the lives of some of their later individuals through hibernation 

 and reappearance in the following spring, of six additional months. Seven 

 species of Catocala give an average duration of forty -five days ; and from Mr. 

 Devereaux's observations, nine species of Catocala give an average period of 

 fifty-seven days. These last may have shown a prolonged period from their 

 record extending over two years — one of which years, from a more favorable 

 season, may have included earlier dates of first appearance. It is proper to 

 state that the above species were selected from the lists, as having been ob- 

 served for the greatest length of time ; the larger number gave considerably 

 shorter terms of apparition. 



In concluding these brief notes, which are quite unsatisfactory to the writer, 

 and offered only in compliance with request, I would beg leave to suggest that 

 good service ma}^ be rendered to Entomology by the collation from published 

 records, and incorporation in our published lists of insects hereafter, of the 

 several dates of their collection or observation throughout the entire time of their 

 appearance. The want of such data has been felt in the attempt to ansv/er the 

 question of Dr. Weismann, [f] as to the duration of life of some of our insects in 

 their perfect state. It would also be of service in the determination of the num- 

 ber of annual broods ; it would aff'ord a knowledge of the time for guarding 

 against the initiative of insect attack; it would enable us in manj'' cases to decide 

 upon the best time fof putting in our crops ; it would enable collectors to seek 

 for specimens fot» their cabinets when they are to be found: in short, it would 

 furnish an essential part of the life-histories of our species. I commend it to the 

 attention of Entomologists. 



* Canadian Entomologist, vol. xi, 1S79, pp. 105-109. 



[tDr. August Weismann, of Freiburg in Baden, Germany, had applied to Mr. W. H. 

 Edwards for this information.] 



