32 ANNALS OF SCOTTISH NATURAL HISTORY 



mountain flora betrays much more specialisation than a 

 mountain fauna. The late Mr. H. W. Bates, F.R.S., com- 

 menting upon the rich collection of insects brought by Mr. 

 Whymper from the slopes and summits of the higher Andes 

 of South America, remarks upon the altitude at which tropical 

 lowland species were found even as high as 9000 or 

 12,000 feet. The difference in this case between the upper 

 and lower environment must be enormous, yet but little 

 variation was perceptible. In the light of these facts we 

 need not be surprised at the altitudes at which so many of 

 our common insects can be found. What is much more re- 

 markable is the presence in numbers on the bare rocky 

 summit of some particular species whose ordinary mode of 

 life would seem to be ill adapted for such an environment. 

 We are therefore obliged to have recourse to some other 

 explanation than the pressure of the struggle for existence. 

 Such species as Donacia discolor, Adimonia suturalis, Serica 

 bninnca, and several others (some of which were taken in 

 numbers), must have been involuntarily carried to the 

 summit through the agency of winds or strong upward 

 currents of air. It is an admitted fact, I believe, that the 

 steering power of beetles is not great, whilst the horny 

 elytra act as vans, putting the insects at the mercy of strong 

 winds. In connection with this subject we may consider 

 the fact that many beetles which are winged more or less 

 perfectly on continental areas, lose their wings or possess 

 them only in an atrophied condition when localised at high 

 altitudes or in oceanic islands, such a resource serving 

 better to preserve the species in relation to those particular 

 environments. Mr. Bruce found quantities of insects on the 

 snow. Is it possible that the white glistering snow-cap 

 has some power of attracting insects ? Or is it simply due 

 to the fact that insects are very clearly shown up on the 

 sheet of snow, and numbers killed by the low temperature of 

 the snow wind ? The thanks of all are due to Mr. Bruce for 

 the great efforts he must have made, during the intervals of 

 arduous work, to get together such an interesting collection 

 of insects. It is hoped that shortly papers will appear on 

 the other insects collected by this gentleman. 



Before enumerating the species, I wish to acknowledge 



