HYMENOPTERO US PARASITES OF RHYNCHOTA. 221 



shows how much there is to learn in this way. These are his 

 Encyrtus triozce, Aphelinus (Agonioneurus) pictus, which is doubt- 

 fully ascribed to Forster, and his Tetrastichus obscuratus (Ann. 

 Soc. France, 1878, pp. 83-5 ; also Bull. Soc. Fr. 1877, p. cxix.). 



39. Trioza magnolia, Ashm.* 

 A Chalcid, Encyrtus solus, is described by Howard from this 

 species (Descr. N. Amer. dial. 1885, p. 15). 



40. Trioza diospyri, Ashm.* 

 In the same work is also described Encyrtus trioziphagus, 

 which preys upon the present species in the Colombia District 

 (p. H). 



APHIDIDiE. 

 41. SlPHONOPHORA. 



Parasites have only twice been bred from unspecified members 

 of this genus. First, Rondani described thence his Chrysolampus 

 aphidicola (Ann. Sc. Nat. Bologna, 1848 ; Bull. Soc. Ent. Ital. 

 1877, p. 170) ; and, second, Ashmead brought forward (Canad. 

 Entom. 1888, p. 104) his Tetrastichine Chalcid, Anozus siphono- 

 phorce, from Northern America. 



42. Siphonophora rosce, Linn. 

 This abundant species is ubiquitously and directly parasitised 

 by the Braconid, Aphidius rosce, Hal. Aphidius proteus, Wesm., 

 is given by Brischke (Schr. Nat. Ges. Danz. 1882, p. 182), A. 

 (Coelonotus) pictus, Hal., and Praon exoletus, Nees, by Gaulle 

 (Cat. 86), and Aphidius ervi, Hal., is said by Marshall to also 

 have been bred from it by Bignell in Devonshire ; all these, if 

 correct, are of far less frequent occurrence than the first species, 

 and hyperparasites have been observed, though none of them 

 from this host. A very full and oft-quoted account of the ovi- 

 position of Aphidius rosce is given by Haliday (Ent. Mag. 1835, 

 pp. 98-99) ; he says the female abdomen is telescopic, and the 

 egg deposited on the under side of the puceron, near its tail ; the 

 female is able to tell if the host be already parasitised ; the larva 

 spins no cocoon, but the imago emerges from the indurated skin 

 of its host. Buckton (Mon. Aph. Brit. i. 110) says both winged 

 and apterous hosts are attacked, adding that the fly poises itself 

 on the back of the Aphid during oviposition (cf. his Aphidius 

 cancellatus, 1. c. pi. iv., which certainly represents A. rosce, female, 



