52 MR. R. J. TILL YARD : LIFE-HISTORIES AND 



much prefer fairly large articles of diet, e. g. very young ^schnine larvse, 

 and Agrionid larvse of all sizes. These they stalk in a very deliberate 

 manner, and very seldom fail to catch them. On the other hand, though 

 they willingly eat mosquito larvse, they do not find them easy to catch. I 

 once saw one snapped at three or four times in succession without effect. 

 Comparing this with the very effective stroke of the much shorter cup-like 

 labium of forms like SyntJiemis, I think it is fair to conclude that the 

 J^jschnine labium is particularly suitable to the capture of fairly large prey, 

 while the narrowness of its lobes, the length of its end-books, and the absence 

 of setse, all combine to make it a much less effective weapon for catching- 

 small prey than is the Libelluline labium. 



The larvBe (two) were apparently full-fed just before Christmas, but 

 remained dormant for a fortnight. For several days before emergence they 

 crawled partly out of the water in the morning. One morning I found both 

 out of the water on twigs, but on my approach they dived back again. The 

 next day I found one of them dead and much swollen up ; the other had 

 crawled up the mosquito-netting and emerged. They were both females. 



The newly emerged insect is semitransparent brown, with pale, almost 

 colourless, spots. In a few days it becomes dark brown with pale yellowish 

 spots. When quite mature the colour is almost black, the markings being a 

 lovely blue-green, very evanescent after death. Eo other member of the 

 genus has spots of this colour. 



All the larvse and exuvia? in my collection (five) are females. It is worthy 

 of remark that, amongst Odonata, the subfamily y^sehnince alone yields to 

 the collector more females than males, both in larvse and imagines. 



Larva ( ? ). — Total length 36 mm., greatest breadth 7'5 mm. across eyes. 

 Head. — 5 ram. ; postocular lobes prominent, 6'2 mm. across, subangular, 

 carrying irregular tubercular swellings which cause the outer border to 

 appear distinctly crenate. Labium. — Mentum 6x4*5 mm., reaching just 

 to mesocoxse, slightly narrowed basally (3 mm.) (Plate 6. fig. 5). Median 

 lobe slightly projecting, slightly bilobed, carrying a row of stiff short hairs 

 and a pair of short stout black tubercles (Plate 5. fig. 4). Lateral lobes of 

 medium breadth, truncate distally, outer apical angle slightly rounded, the 

 inner one toothed ; inner border distinctly crenulate ; movable hook strong, 

 sharp, 1"3 mm. Thorax. — Prothorax 2x5'7 mm., with large bluntish 

 dorso-lateral and two pairs of strong sharp sublateral spines close together. 

 Meso- and metathoraw strongly built, with two pairs of distinct lateral spines ; 

 wing-cases 8 mm. Legs strongly built, black, much spotted with pale brow^Uc 

 Abdomen. — Elongate-oval, well-rounded above, flatfish below. No dorsal 

 spines. Four pairs of lateral spines, those of 6 medium, 7-9 large. 

 Appendages. — Superior 3"6, inferiors 3*9 mm., all strongly triquetral, 

 very sharply pointed, somewhat hairy, tips bent inwards (Plate 7. figs. 5, 17). 

 Tnvolvcres of female imaginal appendages, thin sharp spines, 15 mm. 



