80 THE ENTOMOLOGIST. 



was that of the female of the same species which was taken flying 

 in a street in Devonport on February 24th, 1903.* 



On November 16th the Black Pond was again visited to see 

 if S. striolatum was still on the wing. The latest date on which 

 I had previously seen it was November 14th in 1897, and as the 

 autumn was mild there was a chance of a later date being 

 recorded. None were seen, however ; but it is quite possible that 

 they were not over, for the weather was not altogether favourable. 



Some very interesting notes have come to hand concerning 

 this, which is perhaps the commonest of English dragonflies. 

 Miss D. Molesworth, of Brighton {in litt., Oct. 21st, and again 

 Nov. 6th, 1913), told me that she had had under inspection a 

 number of S. striolatum from the deposition of the egg till the 

 emergence of the imago, the whole life-cycle occupying less than 

 a year. The female was caught ovipositing on September 18th, 

 1912, and, after being kept from water, was on September 20th 

 held over it, when she gave more eggs. These hatched between 

 October 21st and 25th. The nymphs did not grow at a uniform 

 rate, and the wing-cases appeared on the largest towards the 

 end of April, 1913. By June, four of the nymphs had reached 

 a length of 16 mm. and then became restless. There were 

 plenty of water- weeds in the aquarium, but they did not attempt 

 to climb, though earlier in the year many "demoiselles" had 

 scaled the water-plantain leaves and successfully emerged. 

 Miss Molesworth then had to leave them for three weeks and on 

 her return all four were dead. Meanwhile, others had reached 

 the same stage ; but as each attained a length of 16 mm. it 

 died. In August a bank was made in one corner of the aquarium, 

 reaching above water-level, and strips of wood about two feet long 

 were inserted in it. In September the nymphs began one by 

 one to climb to various heights — some to the top, some less than 

 six inches. The first emerged on September 4th and the last on 

 October 12th, 1913. Before the last had emerged, the boards 

 were removed and a bank was built round the water-plantain 

 stems. The nymph climbed and the imago emerged quite 

 happily. That the earlier ones were ready to emerge was clear, 

 for they partially did so under water. The female, from which 

 the eggs were obtained, was depositing them in water not 

 more than six inches deep, and the nymphs were kept in water 

 of about that depth. In water of greater depth they left the 

 bottom and began to crawl on the weeds. In 1913 another 

 female deposited eggs on August 26th, and the first nymphs 

 emerged on September 14th, less than three weeks later, but 

 they were kept in a warm room ! The largest nymph was 4 mm. 

 long on October 21st ; it was observed demolishing a smaller 

 companion. 



■■' Figured, natural size, in ' Entomologist,' xxxvii. pi. 3. 



