280 



THE ENTOMOLOGIST. 



the occiput, the posterior margin of which is also almost straight. 

 The two thoracic spiracles are uncovered and conspicuous. The 

 mask is rather slender and of good length; it broadens somewhat 

 anteriorly, and the inner hook is cut square, while the outer 

 nioveable one is long and sharp. Of the leg-base processes, the 

 hinder one is largest, and a right angle is enclosed between them. 

 The legs, which are fairly stout, are marked with several rather 

 dark rings. In front the abdomen is slightly contracted, but it 

 expands posteriorly, and then contracts again. Segments 7, 8, 

 and 9 have long lateral spines, that on the ninth being almost 

 as long as the tenth segment. The lower abdominal appendages 

 are long and sharp, the middle one is rather shorter and notched 

 at the extremity, while the superior laterals are not half as long 

 as the lower ones. The male projection on the under surface of 

 segment 9 is very small, but that of the female is about two- 

 thirds the length of the segment. 



On July 18th, when Sympetram scoticum was just emerging 

 at the Black Pond, I succeeded in securing a few nymph-cases 

 by looking for the very recently-emerged imagines, and then 

 searching for the nymph-skin on the rushes or reeds below it. 

 Except as a result of breeding, this is usually the most satis- 

 factory method of obtaining nymph-cases whose identity is un- 

 doubted ; in the case of the Agrionines, however, the skins 

 are usually so ethereal that they are of little use. S. scoticum 

 is rather elegant in form, and closely resembles a miniature 

 C. (snea, and might be mistaken for that nymph, only that 

 C. cenea of the same size would be almost or quite innocent of 

 wing-cases. 



Some nymphs of Syinpetrum striolatum, which, as mentioned 

 earlier in this volume (p. 30), hatched out about Oct. 18th, 

 1896, are at present, I am afraid, represented by a single speci- 

 men, but that is now (Oct. 1st) about 16 mm. in length, and 

 certainly will not take two more seasons to reach its full size. It 

 will, I should say, if still living, produce an imago next July, 

 and that although it has not had a plentiful supply of food. It 

 would almost seem that a well-fed nymph might become mature 

 the season following the laying of the egg, instead of taking 

 three years as is sometimes supposed ; but it is just possible 

 that out of doors the eggs may not hatch till the following 

 sjjring. 



Turning now to the perfect insects. The first on the list, 

 Platetrum depressum, was met with on two occasions only— at 

 Longcross, near Chertsey, on June 6th, when I noticed a female 

 ovipositing by dipping her abdomen in the water, apparently 

 quite at random, and at the Black Pond on June 13th. LibeUula 

 qiiadrim'aculata did not appear to be quite so common as usual. 

 I found it between May 9th and July 25th at the Black Pond, 

 the Basingstoke Canal near Byfleet, and Wisley Pond. In the 



