NOTES ON THE LIFE-HISTORY OF CHRYSOPA FLAVA. 129 



full emergence. It is not often one gets a chance of observing 

 this period of the insect's existence, but in the case of the 

 example from which my description is taken the imago was 

 unable through weakness to cast its pupal covering, and remained 

 for two or three days in a helpless condition. Emergence (in 

 the case of those I bred) generally took place in the morning. 



Mr. Main's experience was that, early in the season, a large 

 percentage of emergences took place in the evening, between 

 five and six p.m. Later in the year he observed many freshly 

 emerged imagines, in the same spot, about eight in the morning, 

 as he went to the station ; whilst on the return journey, in the 

 afternoon, emergences were still going on. Mr. Main was fortu- 

 nate enough to be able to make these observations in a place 

 where C. flava was common ; and his notes have the advantage 

 over mine that they were taken from the insects in a state 

 of nature, whereas my imagines were reared artificially. It may, 

 perhaps, be safe to assume that emergences take place throughout 

 the day, in the absence of further evidence, but more observation 

 is needed on this and many other points. 



I was never fortunate enough to see either the emergence 

 of the nymph from the cocoon, or the escape of the imago from 

 its pupal covering. Mr. Main's impression is that the nymph, 

 on emerging from the larval skin, cuts an opening in the cocoon, 

 with jaws specialised for the purpose, and crawls out, the cocoon 

 lid dropping back into its place behind it. He thinks the insect 

 then gets a firm grip with its feet on some near object, and the 

 imago at once escapes, from the splitting of the skin in the dorsal 

 region. His experience coincides with mine in that, in the case 

 of successful emergence, the whole process is a remarkably rapid 

 one ; whilst disturbance generally results in failure to cast the 

 pupal covering and consequent death. 



I am afraid these notes are very imperfect, but Mr. Main, 

 who has kindly sent me larvae from time to time, has asked for 

 such observations as I can with confidence attach to this species. 

 Some of the facts are also from notes taken some years ago, on 

 a former occasion, when I bred C. flava. Other species are 

 under observation, and I hope in time to be able to record the 

 breeding of most of our familiar British members of the family. 

 The larvae are very easy to rear, and give little trouble. More- 

 over, their active existence is short, which makes them suitable 

 subjects of observation for those who, like myself, have not 

 much leisure. Further, I know of no published description of 

 the larvae, which makes their study more interesting ; and with 

 the help of such beautiful photographs as Mr. Main produces, 

 the value of such notes can be much enhanced, the Chrysopids 

 being difficult subjects for the pencil and brush. 



Park House, Worksop, Notts : January 25th, 1911. 



