280 Transactions. — Zoology. 



AntenntE 2 + 14 jointed ; joints of scapus about as long 

 as broad, black, fringed with black hairs ; joints of flagelluni 

 moderately stout, base of lowest joint fuscous, all the rest 

 black, slightly pubescent. Second joint of palpus black, third 

 and fourth joints about equal in length, light-yellow covered 

 with minute yellowish pubescence arid a few scattered black 

 hairs. Epistome black, covered with black hairs. Vertex 

 smoky-grey with moderately long black hairs, and covered 

 with minute silvery pubescence. Thorax covered with minute 

 silvery pubescence, except a median and tw'o lateral black 

 stripes whose surface is shining ; one median line of strong 

 black hairs, which are also scattered all over the surface 

 except on the black stripes. Scutellum black, but covered 

 with minute silvery pubescence and fringed with strong 

 black hairs. Metathorax and pleurae black, but with pu- 

 bescence. Halteres with stout pedicel bearing large oval 

 fulvous clubs apparently naked. Abdomen black, but often 

 with dull - orange patches on the posterior portions of the 

 third, fourth, and tifth segments ; all segments with nume- 

 rous black hairs. Forceps of male large, dull-orange at the 

 base, but darkening upwards, becoming black at the tips. 

 Legs rather long; coxte straw-coloured, darker on the outer 

 surface; femora straw-coloured, covered with short black 

 hairs ; tibiae and tarsi darker and more thicklv covered with 

 black hairs ; sevei'al rows of spines on the tibicE ; spurs 

 rather long, black. Wings with yellowish tinge, surface 

 covered with minute black pubescence. All veins strong, 

 black but lighter near the base ; costal vein extending be- 

 yond junction with second longitudinal, but ending abruptly 

 before the apex ; anterior branch of second longitudinal 

 about eqtial in lengtli to petiole of third longitudinal. 



Female. Length of antennae, 0050; size of body, 0-108 

 X 0044; expanse of wing, 0-176 x 0073. 



Antennae more slender than those of the male ; joints of 

 scapus light-brown ; basal and terminal joint of the flagellum 

 much longer than any others; basal joint dark-brown, others 

 black. Thorax tawny, the black marks bemg represented by 

 dark-brown stripes which unite in a broad patch in front of 

 the scutellum. Scutellum tawny, with a fringe of black hairs. 

 Metathorax and pleurae dark-brown. Halteres as in the male. 

 Abdomen much broader and of a lighter colour than in the 

 male, all the segments being bordered posteriorly with tawny- 

 red. Legs and wings as in the male, but apex of tlie wing 

 much rounder. 



I have assumed that these are male and female forms of 

 the same insect, for, though both forms are extremely com- 

 mon about Lincoln, I have never captured a female of the 

 one or a male of the other. They can be taken all through 



