the others tessellated with black and grey, so as to form irregular transverse bands, 

 the middle segments are without discal setse, and the second one has usually only 

 two bristles on the margin ; scutellum red or yellow ; wings with a spurious 

 appendix, the apical cross vein curved, and the outer cross vein sinuous. 



This well known insect varies greatly in size,* colour, and other characters, 

 and has, therefore, been divided into a number of different species ; several of these, 

 as T. fasciata, Fin., T. Jlavescens, and T. prcepotens, Mgn., are no doubt only 

 varieties of T. larvarum, but Eoudani has described some others, which show slight 

 differences of structure, and may, therefore, be looked upon as distinct species ; two 

 of these I have found, and shall include in my list, briefly pointing out the char- 

 acters by which they differ from the type of the group {T. larvarum). 



T. ^"OCTUAKUM, End. 

 The only points of difference between this and the preceding seem to be that 

 the size is usually rather smaller, the frontal stripe is as wide or wider (in the male) 

 than the sides of the frontalia, instead of being narrower, and that the facial setse 

 do not extend so high up towards the fronto-orbital ones. I have four specimens of 

 this fly, all of which were bred from Odonestis potatoria. 



T. LATIFRONS, End. 

 This species differs from T. larvarum by having the face and pubescence usually 

 white and cinereous, instead of luteous ; by the frontal stripe being wider than the 

 sides of the frontalia, by the eyes in the male being rather more widely separated, 

 and by the facial setse extending higher up, reaching quite to the level of the 

 end of the fronto-orbital ones, or even a little above them. I received a male of 

 this species from Mr. Bignell, bred from ZygcBiiafilipendulcB, and a female from Mr. 

 Fitch, reared from Liparis chrysorrhoea. 



T. EUSTicA, Fin. 

 This is very similar in general appearance and characters to T. larvarum, but 

 differs by having the scutellum black. The face is luteous ; the palpi are yellow ; 

 the frontal stripe is narrower than the sides of the frontalia ; the fronto-orbital and 

 facial bristles nearly meet ; the antennae have the second joint about one-third 

 shorter than the third in the male, and almost as long in the female ; the outer 

 dorso-central thoracic bristles are three in number behind the transverse groove ; 

 the second abdominal segment has four setee on the margin, and two on the disc, 

 and the third segment has four bristles on the disc ; in other points it resembles T. 

 larvarum. Not common ; I received one from Mr. Brunetti, and another from Mr. 

 Coryndon Matthews. 



T. ERUCARrM, End. 



This species is very similar to the last, and is probably a variety of the same. 

 I have only seen one specimen, which I captured in Oxfordshire, it resembles T. 

 rustica in the scutellum being black, and in having three outer dorso-central thoracic 

 bristles ; it differs, however, in having no discal setse on the second abdominal seg- 

 ment, though four are present on the third ; the facial setse are also more distant 



* From 9 — 14 mm. 



