ASCALAPHIDES 



461 



without articulation. Westwood ^ has recently given an account 



of the young larvae of a Ceylonese Ascalax:)hid of doubtful 



species, but possibly Helicomitus 



insimulans; these were observed by Mr. 



Staniforth Green to have the very 



peculiar habit of sitting together in 



a long row on the stem of a plant, 



with the jaws widely extended and the 



body of each one covered by the head of 



the individual next it (Fig. 303, B). The 



little creatures waited patiently in. this 



position until a fly walked between the 



mandibles of one of them, then these 



formidable weapons immediately closed, 



and did not relax their hold until the 



fly was sucked dry. If Westwood is 



correct, the young larva of this species 



differs much from the adult one, the 



back of tlie head being broad and the 



setigerous processes of the body very yiq. 304, 



much more developed. Nearly thirty 



genera of Ascalaphides are known." In 



the genus Hcfplogenius we find an exception to the usual rule 



that the wings in repose are held in a roof-like manner, it having 



been noticed by Bates that in the species in question the wings 



are held expanded as in the dragon-fiies. 



Guilding has described^ a very peculiar mode of oviposition 

 on the part of Ulula macUayana in the island of St. Vincent ; 

 the eggs are said to be deposited by the female in circles on the 

 extremity of a twig, and nearer the base of this there is placed a 

 kind of barrier to repel intruders. " The female may be seen 

 expelling from her ovary these natural barriers with as much 

 care as her real eggs." Guilding's description was accompanied 

 by drawings of the eggs, barriers and larvae, but unfortunately 

 these were never published, and no further information has been 

 obtained on the subject. Hagen ^ suggests that the barriers may 



Larva of Helicomitus 

 insimulans (?). (After West- 

 wood.) 



^ Tr. Entom. Soc. London, 1888, p. 1, pis. 1, 2. 



2 Cf. M'Lachlan, J. Linn. Soc. Zool. ii. 1873, p. 219. 



3 Tr. Linn. Soc. xiv. 1825, p. 140, and xv. 1827, p. 509. 



4 P. Boston Soc. XV. 187a, p. 245. 



