222 On a second membrane 



rax cinereous, with three black lines, the central one double in the 

 female : abdomen shining black in the male, ash-grey in the fe- 

 male ; the second, third, and fourth segments edged with grey in 

 the former sex, and a black dorsal streak along the first four seg- 

 ments in the latter : legs black ; the hinder thighs, and occasionally 

 the others also, more or less fulvous : tibiae sometimes yellowish 

 at the base. Halteres white ; wings slightly tinged with brown, 

 the base yellowish, strongly iridescent. l|-2-| lines. 



Varies considerably, which has caused a variety of names to be 

 applied to this species. It is a common insect in most places, and, 

 besides occurring in flowers, is often seen running about warm 

 banks exposed to the sun. Near London, plentifully in some situ- 

 ations. Neighbourhood of Edinburgh, &c. " Everywhere in Ire- 

 laud, on sunny banks." A. H. Holiday, Esq. 



Myopa pusilla. 



Megerle, Wiedemann, Meigen. 



Antenna? blackish, reddish internally towards the apex : hypos- 

 tome yellow, with a white play of colour ; forehead testaceous : 

 thorax shining blackish-grey, with two black lines dilated behind 

 into a triangular spot : abdomen black, with large light-grey spots 

 on the sides : wings brownish towards the costa : legs shining black : 

 hinder thighs at the base and the knee reddish. 1^ lines. 



We have noticed this insect as it is said to have been taken in 

 the vicinity of London, but there can be little doubt that it is a 

 mere variety of M. atra. 



III. — On the existence of a second membrane in the Asci of Fungi. — 

 By the Rev. M. J. Berkeley, M. A. F. L. S. Plate VII. 



M. Mokren, in a memoir of the highest physiological interest, 

 (Ann. de Sc. Nat. N. S. Vol. v. p. 257-) has lately made known in 

 the short filaments of Closteria, a genus formerly referred to the In- 

 fusoria, but most certainly, according to his most interesting obser- 

 vations, belonging to the order Algae, the presence of three distinct 

 membranes. The external hyaline tube is closely lined with a de- 

 licate flexible membrane ; besides which there is a third sac proper 

 to the green mass of granules and vesicles. It should seem from 

 the analogy of this genus with Zygnema, that the individual Algae 

 are rather to be considered as extremely reduced threads, than as 

 frustules ; in other words, the genus is rather confervoid than dia- 

 tomaceous ; and therefore their relation to the asci of Fungi is per- 



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