161 



absence of earthworms. The non-occurrence of the earth- 

 worm on peaty moors, is probably due to the nature 

 of the soil, but its absence from them must be of no little 

 account in explaining their botanical aspect. 



In investigating the vertical range of animals, more es- 

 pecially invertebrates, in Cleveland, distinction must be 

 made between stragglers to the uplands, and residents on 

 the uplands. The higher watershed between the great dales 

 has not yet been explored by zoologists, and will probably 

 yield rare and interesting species throwing light on the zoo- 

 logical evolution of the district. A few cases are on record 

 of essentially moorland insects occurring in the lowlands, 

 where they cannot possibly have bred since their special 

 food plants are wanting. Thus, the Cotton Grass Moth 

 (Celcena Haworthii) frequents boggy places on the hills, 

 where Eriophorum grows and on which its larvae feed. Never- 

 theless, specimens have been taken by Mr. T. A. Lofthouse, 

 F.E.S., in his garden at Linthorpe, and Emperor Moths 

 (Saturnia pavonia) have also occurred at the electric lights 

 of the ironworks, though the insect is confined to the 

 moors. Facts such as these indicate movements on the part 

 of moths, for purposes that must be wholly conjectural in 

 our present state of knowledge regarding the migrations of 

 Lepidoptera. 



As we shall presently find, numerous animals are peculiar to 

 the moors, but apart from limited or unlimited vertical range, 

 there are indications of a limited longitudinal range of species. 

 I say indications advisedly, for the distribution of many forms 

 is still very imperfectly known, and any conclusions are likely 

 to be rendered nugatory by the discovery of fresh localities. 

 Thus, Aspilates strigillaria, a heath-frequenting moth, has 

 not yet been found by local entomologists further westwards 

 than Danby ; a fact not explicable on the assumption of the 

 westerly ground being inadequately worked, since the insect 

 fauna of that area is much better known than that of the 

 eastern area. The species, however, occurs further eastwards 

 at Cloughton Newlands. The Solitary Ant (Mutitta europcea) 

 seems to be confined to the moors of the seaboard between 

 Robin Hood's Bay and Scarborough. 



