THE 



^.S\> VOLUME XIX. V//X 



ib^ V* 



THE INFLUENCE OF METEOROLOaiCAL CONDITIONS ON 

 INSECT LIFE. 



BT CHAELES G. BAEBETT. 



The means employed by nature to keep species within due bounds 

 — checking theii' inordinate increase or unnecessary decrease — are so 

 certain and reliable in their results, and yet so obscure and diificult to 

 trace in their modes of action, that almost any observations, however 

 slight, which seem to be reliable as data from which to ascertain these 

 means, are interesting and worthy of being put on record. 



In every district and every climate there are evidently many 

 species so peculiarly fitted to it that none of the periodical changes 

 of M^eather and temperature materially affect their numbers, and from 

 these little evidence can be obtained. It is from those species which 

 only casually and rarely extend themselves from their natural homes 

 into cliaiates imsuitable for them, or from those which are always to 

 be found in a given locality, but sometimes rarely, and always varying 

 in numbers, that the most satisfactory evidence must be expected. 



In the first class of cases an example occurred to me a few years 

 ago which seems very much to the point. A friend, a well-known 

 entomologist, being in the South of France and seeing with delight 

 the lovely Deiopeia pulclieUa flying about, captured some, secured eggs, 

 and sent them to a friend in England, who, by great care and assiduity, 

 reared some of them to maturity and again obtained fertile eggs. A 

 few of these he sent to me. They duly hatched, and as it did not 

 seem very likely that any chance of observing native larvae would 

 ever occur to me, I regarded them with great interest. They were 

 supplied with several species of Myosotis, but only about half a dozen 

 of them seemed to possess sufiicient vitality to feed, and as these 

 evidently preferred Myosotis pahistris, I potted some plants and kept 

 them growing in a sunny window, where the young larvae, covered 

 with gauze, made themselves tolerably comfortable and grew rapidly, 

 feeding with especial eagerness when the sun was shining on them. 

 The weather happened to be fine and the sun hot for two or three 



1882. 



