AGRIUS CONVOLVULt. 



345 



i on August 19th, 1 90 1, at Cornhill, near Dover, a second a few days 

 later (Mathew); 2 larvae on August 19th and 21st, i9oi,at Boxworth, 

 on bindweed (Thornhill) ; 13 larvae between August 20th and 

 September 3rd, 1901, at Sudbury ; also a pupa on August 

 22nd (Ransom); 3 larvae on August 21st, 1901, at Kirklebride, 

 and 2 on September ioth-nth, 1901, at Dunbar (Evans); a fullfed 

 larva on August 23rd, 1901, at Angmering, which pupated in due 

 course (Dollman) ; 1 fullgrown larva on August 23rd, another on 

 August 26th, also a pupa a few days later at King's Lynn (Atmore) ; 

 a larva on August 24th, 1901, at Guestling (Bloomfield) ; 1 fullfed on 

 August 26th, 1901, at Chilwell, this buried on August 2.9th (Pearson); 



1 nearly fullgrown larva on August 28th, 1901, at Dawlish (Main) ; 

 a larva on August 28th, 1901, at Mucking (Burrows); larva 

 on August 28th, 1901, at Ilford, pupated September 5th (Adams); 

 5 fullgrown larvae at Monkton, nr. Roystone, between August 30th 

 and September 2nd, 1901, on Convolvulus arvensis (Whitaker) ; 50 

 larvae in August and September, 1901, at Seaton Sluice, on Convul- 

 vulus septum, of which, all but one went down for pupation, (Proudlock 

 teste Robson); 4 larvae and 1 pupa between August 2oth-29th, 1901, at 

 Hadleigh (Whittle) ; 1 nearly fullfed at end of August, 1901, in 

 Hayling Island (May); 5 larvae and several pupae August and September, 

 1901, at Bournemouth (Crallan) ; a pupa taken in a garden at 

 Folkestone in August, 1901, produced an imago on September 20th, 

 in a warm room (Hills, Ent. Rec., xiii., p. 335); a pupa on September 

 4th, 1 90 1, on the Sussex coast, among C. arvensis and C. septum 

 (Frohawk); a pupa dug at Haddenham on September 19th (Barton) ; 



2 larvae and 3 pupae from September 6th-2oth, 1901, at Ringwood, 

 from two of which imagines emerged October 3rd and 14th (Fowler). 



Duration of larval life and rate of growth. — In his 

 excellent account of this species, Poulton details (Trans. Ent. Soc. 

 London, 1888, pp. 550 et seq.J the average duration of the egg stage and 

 each of the larval stadia, and gives a comparison of the growth of the 

 larva at the end of each stadium. His tabulation works out as follows : 



duration of time for 



length of larva 



Development in the egg 



10 days 



1st larval stadium 



9! days 



2nd larval stadium 



8 days 



3rd larval stadium 



8| days 



4th larval stadium 



12 days 



5th larval stadium 



13 days 



Newly hatched 

 At end of 1st larval stadium 

 At end of 2nd larval stadium 

 At end of 3rd larval stadium 

 At end of 4th larval stadium 

 At end of 5 th larval stadium 



375mm. 

 8"25mm. 

 140mm. 

 24"Omm. 

 41-omm. 

 8o*omm. 



Poulton says : " Each of these figures was estimated from the data 

 given at the end of each stage (loc. et't.J. The whole period of larval 

 life may be taken as extending from about September 8th to about 

 October 29th — a period of 51 days. It appears probable that an 

 unusually short development in the egg only causes a corresponding 

 protraction of the first stage; and it is also probable that larvae 

 emerge from the egg with very varying amounts of unassimilated 

 nutriment, and that those with the smaller amounts have carried 

 on the process of assimilation to a greater extent in the egg itself, 

 and, therefore, emerge at a comparatively late period, while, con- 



