1 67 

 WHY IS BOREUS A WINTER INSECT? 



CHRIS. A. CHEETHAM. 



This question was suggested on finding Boreus last November* 

 and by seeing springtails in plenty on the snow the same 

 month. A possible reply suggested that its food requirements 

 were available at such times, and it seemed desirable to in- 

 vestigate the fauna of the mosses from the limestone walls 

 where Boreus occurred. 



For this purpose some large patches were gathered, shaken 

 and sifted with surprising results to a novice at such work. 

 Springtails were in plenty, and seemed to offer the most likely 

 answer to the query. Mr. J. M. Brown kindly examined 

 the collection, and states that the following were inchided: — 



Isotoma sensibilis TuUb., 3 specimens. 



/. viridis Bourl., many. 



Tomocerus vulgaris Tullb., about 12. 



Entomobrya nicoleti Lubb., i specimen. 



Orchesella cincta Linn., many. 



0. cincta var. vaga Linn., several. 

 He says that these are not specially ' winter forms.' 



The Pseudoscorpions, Spiders and Mites were named by 

 Mr. W. Falconer, with a similar result as to winter restricted 

 forms. His list includes : — 



PSEUDOSCORPION. 



Obisium muscorum. Both sexes and all ages, some being 

 unusually dark. He queries this as perhaps due to the 

 sun's heat, together with open habitat and elevation. 

 Spiders. 



Cryphoeca silvicola, $, (^ . 



Amaurobious fenestralis, 1 immature $. 



Oonops pulcher, $, c?. 



Oxyptila trtix BL, (^, imm. 



Diplocephahis fuscipes BL, ^. 



Panamomops bicuspis, (^ . No other Yorks. records west 

 of Collingham. 



Lophocarenum nemorale, (^ , $. New to V.C. 64. 

 Harvestman. 



Megabunus insignis Mde., 9- 



Mites. 



Damaeus clavipes, ^ {Oribaiidae) . 



Gamasus crassipes, 5, (^ {Gamasidae) . 



Pergamasus runciger, $ [Gamasidae). 



Cyrtolaelaps kochii, $, [Gamasidae). 



Bdella vulgaris Herm., $ (Thrombiidae). 



Eothrombium echinatum, $ (Thrombiidae). 



* See The Naturalist, 1921, p. lO. W. J. Fordham points out that 

 it was previously recorded for the county by J. W. H. Harrison, in The 

 Vasculum, 1915, p. 57. 



1921 May 1 



