NOTES ON BRITISH ODONATA IN 1920. 5 



Fabr. was _ on the wing in the New Forest, though it was 

 only occasionally that a blue specimen was seen (Lucas). 

 On 30 May in Oberwater, New Forest, I found three naiads* 

 of what I presumed to be 0. cceridescens and took them away 

 with the hope of breeding them. On the morning of 10 June 

 a male was found to have emerged since the previous evening, 

 and was hanging about 9 a.m. (s.t.) with wings pressed together 

 over its back. About an hour later it had spread its wings, 

 which were seen to be very glossy. The pterostigma was 

 yellowish, and the body various shades of brown with yellowish 

 markings. The insect was a male, and 0. ccerulescens as I 

 expected. On 14 June it was moribund. It had been kept 

 under a glass shade and had eaten nothing. Some of the 

 gloss had disappeared from the wings, but the "cerulean" 

 bloom had not developed on the abdomen. Another male 

 emerged on 22 June. It had been on a stick above water about 

 a couple of days, but remained wet (perhaps the tip of the body 

 touched the water, which spread over its hairy surface). The 

 third specimen was put in formalin for figuring and description. 

 The latter follows : 



Description. — Body generally of a rather warm sepia tint (but 

 the colour is often hidden, the body being incrusted with mud or 

 decayed bog material) ; hairy ; somewhat cylindrical above, and there- 

 fore not so much spread out as some Libellulines. Length including 

 appendages some 19 mm. ; greatest breadth about 5-5 mm. Head 

 somewhat pentagonal in shape ; transversely about 5 mm. ; fairly 

 broad from front to back — -about 3-5 mm.; top of head (epicranium) 

 convex ; occiput well developed, hind margin a little concave. 

 Antennce of 7 segments, basal two short and swollen, the next 

 slender and about equal in length to the basal two together, the 

 rest slender and sub-equal ; hairy. Eyes — the spherical part 

 prominent at each fore corner of the head, with a prolongation 

 backwards reaching about one-third across the head. Labium. 

 (mask) rather short; but just extending beyond the insertion of 

 the fore legs ; spoon-shaped ; deeply concave ; inner surface bearing- 

 scattered hairs (or slender spines) ; submentum narrow ; mentum 

 becoming rather suddenly broader; mid lobe finely crenated, with 

 about 13 crenations on each side of the mid point, a minute spine 

 in each depression ; mid lobe making a decidedly obtuse angle in 

 front, produced centrally into a blunt point, a short ridge leading 

 up to the point internally ; lateral lobes (palpi) triangular, concave, 

 distal border with a few (about 7) shallow crenulations and 

 irregularly arranged spines near the margin; inner margin entire; 

 outer margin entire and considerably thickened ; mental seta in two 



* Comstock in his "Introduction to Entomology" (Ithaca, 1920) proposes 

 (p. 179) to restrict the term "nymph" to the immature instars of insects with 

 gradual metamorphosis (e.g. grasshoppers), to use the term naiad for those 

 with incomplete metamorphosis (e.g. dragontlies and mayflies), reserving the 

 terms larvce andpit/w for the earlier stages of insects with complete metamorphosis 

 (e.g. butterflies and beetles). As there seem to be advantages in this arrangement. 

 I have used the term naiad in this article. 



