180 January, 



gular spot on the posterior margin of tlie second segment, and into a similar smaller 

 one on the edge of the third ; there are very few bristles, except upon the sides and 

 apex. 



Wings hyaline, yellow at the root ; there is no costal spine ; the internal trans- 

 verse veins are placed opposite the termination of the auxiliary veins ; the external 

 transverse veins are nearly straight, but placed obliquely. 



Calyptra have yellow scales with bright orange margins. 



Halteres small, with dull yellow stalks and grey heads. 



Legs rather long ; middle tibiae with a series of bristles of moderate and equal 

 length along the whole of their external and posterior surfaces, and also with a 

 number of long spines at their extremities ; hind femora clothed with long soft 

 hairs ; hind tibiae distinctly curved towards their extremities, furnished with long 

 hairs on the whole length of both their outer and inner sides, and with a series of 

 spines on their posterior surfaces. 



This species seems to be rare. I have only seen a single male, which I captured 

 in August, 1883, in the Woods near Bolton Abbey, in Craven, Yorkshire. It bears 

 a considerable resemblance to P. albo-lineata, but differs from it by being larger, by 

 having four instead of two wide stripes upon the thorax, by the hind tibise being 

 curved and very hairy, as well as by other characters. 



HTETODESIA, Mde. 



H. TEIGONALIS, Meig. 



This species, which is abundant in the Lake District about Windermere, as well 

 as in the South of England, was recorded in my list under the name of II. lata, 

 for which I mistook it. Mr. Verrall pointed out the error to me, and has recorded 

 the name of the fly in his " Hundred New British Species of Diptera ;" he includes 

 it, however, in the genus Spilogaster, but the eyes are distinctly hairy (the cause of 

 my mistake), therefore, it must be correctly placed among the HyetodesicB. It re- 

 sembles II. Iceta, and also Spilogaster fuscata, by having a series of triangular 

 black marks down the back of the abdomen. It differs from II. Iceta (which 

 has not yet been recorded as British) by having, like H. serva, only three posterior 

 dorsal bristles on the thorax in the two parallel rows of setae which are placed in 

 the space between the middle and lateral stripes, while there are four in II. Iceta j 

 the eyes of the male are also closer together (being contiguous) in II. trigonalis 

 than in II. Iceta, in wjiicli they are only approximate ; the scutellum has two lateral 

 black marks in the former, while there is only one basal mark in the latter ; the 

 tibise also are much lighter in colour in H. trigonalis than in H. Iceta. It may be 

 at once distinguished from S. fuscata by the eyes being hairy. 



H. BASALTS, Zett. 



In the female of this species the eyes are almost bare, therefore, unless examined 

 under a strong lens, it may easily be mistaken for the female of Mydcea urbana, 

 which differs from the male in having the fore femora yellow like the posterior ones ; 

 the former species may, however, be easily distinguished from the latter by the form 

 of the epistome, which is much more prominent in H. basalis than in M. urbana. 



