BY H. J. TILLYAHD. 261 



enclosed the shoulders of the female, over which tliey fitted 

 exactly. When the male exerted his full strength, these were 

 pressed so far down as to bring the back of segment 10 of his 

 abdomen into contact with the thorax of the female, and, at the 

 same time, the head of the latter came back so far that the 

 superior appendage became firmly wedged between the shoulder 

 and the back of the eye. This pair was killed and set in position, 

 but, during the process of drying, the original rigid position could 

 not be retained. The sketch in Plate xxiv. (fig.l) shews them as 

 they are at present in my collection, and may be taken to 

 represent exactly the position of the appendages of the male on 

 first seizing the female. It can be easily seen how further down- 

 ward pressure would bring the dorsum of segment 10 of the male 

 on to the thorax of the female, and the back of the eye of the 

 female on to the superior appendage of the male. The whole 

 position gives a strong grip, and justifies the existence of the 

 petaloid appendage as a useful organ. 



The most remarkable feature of it is, I think, the position of 

 the inferior appendage. The occiput of the female has no large 

 prominences or depressions, but its slightly raised surface seems 

 to tit exactly the broad appendage of the male; while the curva- 

 ture of the latter is such that the application of downward 

 pressure from the abdomen forces the head of the female back, 

 and, at the same time, keeps the appendage firmly in position where 

 a slightly straighter appendage would most certainly slip. 



When firmly held together, the pair rises into the air, and 

 after a few preliminary evolutions makes straight for some high 

 tree, on the branches of which they settle during the act of 

 copulation. I have sometimes seen a second male, or even two, 

 attack them when paired, but they did not succeed in eff'ecting a 

 separation. The seminal vesicle appears to be charged by the 

 male after jyairing and during the gyratory flight. He doubles 

 himself completely up, and evidently only effects the operation 

 with some difficulty, as he has to keep a firm hold of the female 

 and also raise her with the end of his abdomen. 



Oviposition. — After copulation, the pair separate, and the 

 female hides herself in the teatree scrub at the head of the marsh. 



