248 Transactions. — Zoology. 



Anteiinai dark-brown ; joints cylindrical, with very short 

 pedicels ; terminal about half as long again as the penultimate 

 joint ; a circlet of short verticils arises from the basal portion 

 of each joint. Lower portion of frons black. Three ocelli, 

 situated in a triangle just above point of insertion of the 

 antennae. Compound eyes far apart, emarginate, the antennae 

 being situated in the bend in the outline. The antennas are 

 nearly surrounded by a single row of facets, bead-like in ap- 

 pearance. Palpi light-yellow. Thorax dark-brown, hood- 

 shaped ; two stripes of lighter colour inclined to one another 

 like the sides of a wedge, the point directed posteriorly ; on 

 these stripes long hairs are situated. Scutellum dark-brown, 

 with a rovv of hairs along posterior margin. Halteres with 

 short pedicels ending in elongate pyriform clubs ; light - 

 brown in colour, with scattered black hairs. Abdomen dark- 

 brown, anterior portion of third and succeeding segments 

 light-brown. Surface of all the segments with slender light- 

 coloured hairs. Legs not much longer than the abdomen ; 

 light-brown femora, rather shorter than tibiae ; latter light- 

 pink at the tip ; *first joint of tarsus more than double the 

 length of the second, others all shorter than the one pre- 

 ceding them. Wings pellucid, covered with scattered short 

 black hairs. Costal and second longitudinal pink ; rudiment 

 of auxiliary vein present ; first longitudinal more than one- 

 third the length of the wing, cross-vein near its tip very 

 oblique ; second longitudinal ending long before the tip of 

 the wing; third longitudinal branching out of second just be- 

 fore junction with cross-vein, fork long, both branches wavy, 

 anterior branch ends at the tip of the wing ; fourth longitu- 

 dinal commencing nearer base of wing than third longitudinal, 

 nearly straight, almost disappears before reaching the margin ; 

 fifth longitudinal distinct, strongly arcuated ; sixth longitu- 

 dinal short, lying close alongside fifth longitudinal. Posterior 

 angle of the wing very distinct. 



Lincoln. Fairly common, especially in very early spring, 

 but is found all tbe year round. 



Male. Antennas, 0-055 (largest), 0-035 (smallest) ; wing, 

 0077 X 0-030 (largest), 0-060 x 0-024 (smallest) ; body, 

 0052X 0-011 (largest), 0-046 xOOll (smallest). (Plate VI., 

 fig. 2.) 



Antennae light-brown, 2 -f 14 joints; joints cylindrical, 

 with pedicels twice their length ; all the joints appear double ; 

 ornamented with rather long verticils arising from the con- 

 striction in the middle of the joint ; terminal joint oval, larger 

 than those innnediately preceding. 



At first I thought that there were three distinct species, 

 which, on examination, proved to differ only in size. This, 



