NEMATOCERA. 75 



Sub-Genus. — Diplosis^ Lw. 

 D. coniophaga, Wtz. = C oidii, Hardy (Scot. Gard., 1854, p. 170 [?]). 



The larvae of this species live on the leaves of various plants, 

 especially on the following : Betula, Populus, Rosa and Salix ; Bergen- 

 stamm and Low also give Cirsium and Lachica. Walker says " they 

 live with D. Ceomatis* on Ceoma miniatiiin, on the fallen leaves of 

 Rora, and feed on that fungus."! They feed on the spores of the 

 fungi, and pupate in the ground. 



The i?fiago is yellow, the dorsum has three brown markings ; 

 abdomen, each segment has white hairs upon the posterior margin ; 

 legs brown ; wings transparent, with thick gray hairs (Schiner) ; 

 transverse veinlet joining the middle of the first longitudinal vein, 

 f to f lin. 



r Tipula loti, Deg. 

 D. loti, Deg. = .^ ^^^.^^ ^^^.^ Meigen. 



The larvae of this species have the power of leaping well de- 

 veloped; this saltatorial habit seems common to this sub-genus. 

 Low remarks " that all such larvas belong to the sub-genus 

 Diplosis."X If '^his is the case, C. nigra § belongs here. The larvae 

 of loti live in the flowers and in the husks of the seeds of Lotus 

 corniculatus, Medicago sativa and Vicia cracca. Many larvae may 

 live in the same flower-head and form curious gall-like deformations. 

 They pupate in the ground. 



Imago. — Blackish-brown ; neck and scutellum dirty whitish-yellow ; 

 scutellum with yellowish little hairs. Wings have a dark pubescence 

 and brown veins, dorsum has two rows of whitish-yellow hairs. 

 Ovipositor large, black, yellowish in parts. 



D. trenmlce, Wtz. — " The Aspen Gnat." 

 _ ( Tipuia poptdea, Schrank. 

 ( Cecid. polymorpha, Bremi. 

 The larycell of the " Aspen Gnat " seem to form two kinds of galls; 

 the first are formed on the leaves of Populus tremula— these are red 

 galls the size of a pea — the second kind is the well-known gall formed 

 on the leaf stalk : each gall is inhabited by a single larva, which 

 pupates in the ground (Winnertz). 



Imago. — Dorsum blackish-brown, with two rows of whitish-yellow 



* Described by Walker, but only considered a reputed species by Verrall. The 

 four brown spots on the white wings easily distinguish this species from D. conio- 

 phaga. 



t Ins. Brit, viii., p. io6. '■ Rora ' being a misprint evidently for Jiosa. 



J Mon. of N. American Diptera, Osten-Sacken, pt. i., p. 183. 



§ Vzde note at end of Chap. IV. 



II Vide pi. i., fig. 2, vol. viii., Lin. Entomologica. 



