250 The Scottish Naturalist. 



union in former times of the Shetland Islands to the Scottish 

 mainland, and by the not-to-be-under-valued influence of the 

 Gulf Stream. 



The importance of the fauna lies in the very interesting varie- 

 ties that it exhibits, and all entomologists must thank Mr. M 'Arthur 

 for his continued and careful researches in this distant locality, 

 carried through under difficult circumstances. 



A NEW GALL-MIDGE (BormomyU Abrotani sp. n.). 

 By Prof. J. W. H. TRAIL. 



In October, 1884, 1 found on a plant of Artemisia Abrotaniwi (Southernwood), 

 in a garden in Old Aberdeen, numerous small galls on the leaves, usually on 

 the upper surface near the origins of the lobes ; frequently half a dozen or 

 more occurred on a leaf. They are like a rifle bullet in shape, fixed to the leaf 

 by one side, with the tip free. Their size is only T V by ? V inch. The free wall 

 is thin. The surface is like that of the leaf ; the colour was yellowish-green o r 

 dull reddish-green. In each lived an orange-red larva, which almost filled the 

 central cavity. From galls kept in a box during the winter a number of the 

 midges, of both sexes, emerged. They seem to come nearest to Cecidoniyia 

 foliortim H. Lw., but differ in so many points from that species, as described 

 by Loew, that I venture to regard them as unnamed, and propose to call them 

 Hormomyia Abrotani. I subjoin a description. 



Hormomyia Abrotani sp. n. 



Male, brown, without red or darker spots, eyes black. Thorax humped in 

 front. Antennae 14-jointed, joints elliptical, stalked, with a circle of long 

 hairs on each. Wings narrow at the base, but suddenly widened at about 5 of 

 their length, grey, concolorous throughout, with darker veins : 1st vein not 

 very near costa, which is not much wider after the vein has joined it ; 2nd vein 

 hardly to be made out at the base, the very oblique pale cross-veinlet looking 

 like the basal part of it ; the 2nd vein is slightly curved in its more distant half, 

 and does not quite reach the outer margin of the wing ; if continued, it would 

 reach this at, or a little behind, the middle ; 3rd vein is distinct in its basal half, 

 but stops abruptly before the point where the fork is usually situated, and shows 

 no trace of either branch. Halteres pale grey. Legs long and slender, uniform 

 brownish. Length of male insect 0*5 inch (1 mm.) 



Female resembles male, except in larger size {^ inch, or i| mm., with ovi- 

 positor exserted), and in the uniformly brownish red abdomen, with along tele" 

 scope ovipositor, which is red towards the tip. The antenna? are alike in the 

 two sexes. The abdomen in both males and females bears only pale incon- 

 spicuous hairs. 



The above description is taken from dried insects. 



