224 STUDIES IN AUSTRALIAN VEUROPTERA, iii., 



Finally, I had a large suppl}' of larv?e and pup?e of a connnon 

 species whose larva is found in all citrus-orchards around Sydney, 

 as well as on rose-bushes. The cocoons were smaller than I could 

 have wished, and the pupa? delicate enough to give me much 

 trouble and many failures before good results could be obtained. 

 But I was able to breed a number out, so as to obtain an imaginal 

 venation-scheme exactly corresponding with the pupal wing-tra- 

 cheation studied; this was, indeed, an c-ssential condition for a 

 successful result. This species proved to be one which had pre- 

 viously been determined for me by Mr. Esben Petersen as C. 

 sujnata Walker. It turned out, therefore, very fortunately, that 

 I am able, after the comparative failure of the work done on the 

 unnamed species, to offer a result based in almost every detail of 

 completeness upon the venation of a single, common, named 

 species. 



Methods of Study. 

 The problem was first attacked along the exact lines already 

 laid down for the study of the tracheation of the pupal wing in 

 the Mynneleuntidie.. First of all, the exact date of the spinning- 

 up of each larva was recorded, and the cocoons arranged accord- 

 ing to date. Here, at the very start, an attempt to use the 

 knowledge gained in the case of the Myrm.elmntid(t' led to disaster. 

 It will be recalled that the Ant-lion larva does not j^upate at 

 once after spinning its cocoon, but remains tpiiescent within it 

 for seven or eight days. I thei'efore kept a number of cocoons 

 of the large Nothochrysa for several days, examining them care- 

 fully in a strong light each day. After four or fi\-e days (by 

 which time the cocoons must have been seven or eight days old, 

 since they had spun up before Mr. Gallard jjosted them to me), 

 the contents began to darken in colour. The larva Ijeing covered 

 with a white powdery bloom, I concluded that pupation liad 

 taken place. This was, alas, not the case; the darkening was 

 due, not to the pupation of the larva, but to the pujjation of 

 half-a-dozen or more ichneumon-grubs within it. Thus several 

 valuable days were lost; so that, when at last a cocoon was opened 

 which revealed a Chrysopid pupa, it was much too far advanced 



