60 MR. R. J. TILLYARD : LIFE-HISTORIES AND 



voluntarily from any other female ^Eschnine. The ova measure 1*2 xO"4 mm., 

 in shape elongate-oval, somewhat broader than usual in ^Escltnince (Plate 9. 

 fig. 22). In spite of much careful waiting and watching, this was the only 

 time that I ever saw this species ovipositing. 



Putting all these facts together, it seems reasonable to suppose that this 

 species has thrown over the ancient but laborious usage of its relatives, who 

 oviposit in moderately hard tissues by means of their rasping-apparatus or 

 dentigerous plate, and has adopted the method of simply boring into softer 

 green tissues. I should like to be sure how this is done, but my own opinion 

 is that the female bends her body round until she can ram her sharp spike 

 into the tissue, makes the hole large enough, and then simply slips the egg 

 into the hole. One can scarcely credit the much abbreviated terebra with 

 any great powers of guidance, much less of boring. 



The flight of this species is strong and long-sustained, very much like that 

 of Anax jjapuensis. It is therefore interesting to note the great strength of 

 the anal triangle of the male and the strong anal angle, both built on the 

 exact plan of a typical Avstrocesclina, only " more so." Now, in Anax, such 

 a structure could not have been developed, since its ancestors undoubtedly 

 possessed the long and narrow anal triangle typical of -ZEschna, and fringed 

 by a very long membranule. The wing-strengthening therefore took an 

 opposite turn, ending in the complete abolition of the weak anal triangle and 

 the formation of a strong rounded wing. Both final types give a fine result 

 in flight-power. The strongly angulate wing seems to be superior lor 

 darting, the rounded wing for soaring and skimming. The two forms 

 reach their maximum developments, the one in Macromia, the other in the 

 Libellulince. The shifting of the arculus sectors upwards must also not be 

 lost sight of as a factor for strength in both Notocesclina and Anax, while 

 much of the sustained power of flight is due to the great strength of the 

 wang-niembrane and veins themselves. 



Larva. — Total leiiytli 37*5 mm.; greatest breadth 8'5 across segment 6. 

 H e a d. — 5"7 mm. ; breadth across eyes 7 mm. ; postocular lobes well rounded, 

 smooth. Labium. — Mentum 4'5 x 5 mm., broad and short, reaching back 

 only to between procoxse, where it is reduced to 3 mm. width (Plate 6. fig. 9). 

 Median lohe projecting as a very obtuse triangle, without median depression, 

 hairs, or tubercles. Lateral lobes narrow, apex well rounded, inner margin 

 not crenulated, movable hook rather thick and short, 1'2 mm. (Plate 5. fig. 8). 

 Thorax. — Protliorax 2'7 X 7 mm., with very blunt dorso-lateral and two 

 paii's of sharp sublateral spines. Meso- and metatliorax fairly smooth, no 

 spines ; wing-cases 8 mm. Legs very strong and large ; proferaora 6 x 1"8 mm., 

 flattened, and carrying a strong dorso-basal spine ; 2nd femora 8x 1*9 mm.; 

 hind femora 10 X 1'9 mm., both without spines but much flattened ; tibia? of 

 medium width, rather flattened ; tarsi with large diverging hooked claws. 

 A b d o m e n. — Of the usual shape, but carrying small nodding dorsal spines 



