228 Transaciiv)is. — Zoology. 



difficulty to see tliem witli the nalced eye. On account of 

 their fragile nature they are extremely hard to set, and if left 

 in a glass tube where there is any trace of moisture they 

 quickly become dismembex'ed, and their wings are injured. It 

 is advisable to carry the materials for setting the insects 

 whilst collecting, as one can then be sure of setting good 

 specimens still uninjured. If in my excursions last summ.er I 

 had been provident enough to carry the materials for setting 

 with me I should probably have double the present number 

 of species to describe. During the forthcoming spring and 

 summer, however, I hope to profit largely by my experience of 

 last year. 



Structure of Imago. 



The head is small, broader than long ; round when viewed 

 from the front. Eyes generally lunate or reniform, more or 

 less contiguous on the front. Ocelli wanting in the sub- 

 family Cecidomyina, but extant in the Lestremina. Pro- 

 boscis short, thick, fleshy, directed towards the pectus. Palpi 

 prominent, four-jointed, the first joint short, the last usually 

 the longest. Antennae long, moniliform or cylindrical, generally 

 verticillate-pilose, seldom without verticils, ten- to thirty-six- 

 jointed, of which the basal joints are more or less cupuliform ; 

 flagellar joints sometimes pedicelled in the male and sessile 

 in the female, sometimes of the same structure in both sexes. 

 The thorax rounded, in some species gibbose, sometimes ex- 

 tending over the head in the form of a hood ; without a 

 transverse suture. Halteres never completely bare, often 

 considerably haired or scaled ; the pedicel long and slender, 

 the club large. Legs generally very long and slender ; cox® 

 short, femora not thickened, tibiae without spurs, tarsi five- 

 jointed, the metatarsal joint much shortened in the first sub- 

 family ; claws weakly developed, with apparently only one 

 cushion. Wings incumbent, proportionately long and broad, 

 rounded at the apex, cuneiformly narrow^ed at the base ; as a 

 rule hyaline, though sometimes pellucid, with a pale bluish or 

 brownish tint ; generally beautifully iridescent ; sometimes 

 marmorated ; more or less covered with irregularly-arranged 

 hairs ; occasionally scaly ; all the anterior margin scalous ; 

 deeply ciliated at the apex and posterior margin. The 

 number of longitudinal veins amounts to at least two, or at 

 most five — never less than four in the second sub-family, or 

 more than four in the first sub-family. In both sub-families 

 the last two longitudinal veins coalesce for more than half 

 their length, forming beyond a more or less distinct part. 

 The additional longitudinal vein of the Lestremina is inserted 

 between the second and third veins of the first sub-family, and 

 is furcate in all genera but Gampylomyza. A longitudinal 



