210 ANNALS OF SCOTTISH NATURAL HISTORY 



ON THE OCCURRENCE OF A NEW BRITISH 

 FLY (TRICHOCERA MACULIPENNIS, MG.) 

 IN THE FORTH DISTRICT. 



By PERCY H. GRIMSHAW, F.E.S. 



DURING a visit to a coal mine on the ipth of July this year, 

 my enthusiastic friend, the Rev. James Waterston, came 

 across a single female specimen of Trichocera maculipcnnis, 

 Mg., clinging, in absolute darkness, to the wet surface of the 

 side of a gallery 168 feet below the surface. This interesting 

 discovery was made near the foot of the shaft at the Croft 

 Head Colliery, Fauldhouse, and is worthy of record inas- 

 much as the species has not hitherto been recognised as a 

 native of Britain. A year or two ago, however, I saw a 

 specimen of the same species from a cave in Derbyshire, but 

 under circumstances which prevented my alluding to the fact. 

 This second occurrence, therefore, enables us to regard this 

 distinct species of " Winter Midge " as an undoubted member 

 of our Fauna. The flies of the genus Trichocera possess 

 interesting habits, being lovers of cold. 



The common species T. hiemalis, Deg. and T. regelationis, 

 L. both occur in the depth of winter, and, according to Mr. 

 Eaton ("Nature," April 14, 1 88 1), fly principally during a 

 temperature of 40 to 45 Fahrenheit. T. regdationis and 

 T. maculipennis are both recorded by continental observers 

 as occurring in mines and caves, the former often at a depth 

 of 100 fathoms. 



Trichocera maculipennis, Mg., may be readily distinguished 

 from all other members of the genus by the fact that the 



wings are decidedly spotted 

 (see figure), the spots being 

 due to a conspicuous cloud- 

 ing of the base of the radial 

 (2nd longitudinal) vein and 

 also the marginal and small 



cross veins ; also a less conspicuous clouding on the discal 

 and posterior cross veins. So far as my experience goes, no 

 other species of the genus shows more than the slightest 



