ON THE ARTHROPODS INHABITING MOLENESTS. 61 



fluous to state that such a task has been undertaken, and, with a 

 thoroughness characteristically Teutonic, completed by a German, 

 Father Heselhaus of Sittard, and the reprint, which lies before us, 

 contains the result of his investigations. 



It is, perhaps, curious that, although Dr. Joy's researches had been 

 given to the world at least four years before our present author under- 

 took his investigations, he only alludes to the English Doctor once, 

 perhaps somewhat doubtfully as " der engleschen Forscher," and once 

 by name as among authorities cited by Bickhardt, although he admits 

 in limine that the stimulus to the investigation of molenests came to 

 him, among other sources, through the kindness of a colleague, whereby 

 he was enabled to look through an English magazine, where the good 

 prospects attendant on an investigation of the nests of different 

 mammals were pointed out,''' but that which finally fixed his attention 

 on this subject was information received from Dr. Everts that R. 

 Heinmann, a Coleopterist of Brunswick, had dug up some 100 nests 

 in that district and discovered in them no less than 2,000 beetles 

 referable to 90 species. 



The theatre of Father Heselhaus' own operations seems to have 

 been principally some swampy land in the immediate vicinity of his 

 own town of Sittard. His digging began in the winter of 1910-11, 

 during which he tells us he found but little. Unlike his English 

 colleagues, he appears to have been able to find and explore molenests 

 to some extent during the summer, but it was during the winter 

 1911-12 that most of his work was done and the great body of his 

 list compiled. 



We gather, although we may be mistaken in this, that although 

 Father Heselhaus seems to have noted every arthropod, indeed, every 

 Jiving creature found in his nests, he is not himself a specialist in any 

 group, since other authorities are responsible for nearly all the names ; 

 and to this defect, if it be a defect, is probably due the indiscrimi- 

 nating completeness of the inventory. Put a specialist in any order 

 down to attack molenests, and he will probably become so interested 

 in the manifestations of his own particular group there, that he will 

 be more or less blind to those of any other, but for Father Hesel- 

 haus a Dipteron was evidently as good as a beetle, and an Acarus as 

 either, and hence no one group has been favoured at the expense of 

 any other. In this list then, in addition to a passing notice of a 

 mouse as representing the Vertebrata — four classes, viz. : — 



Insecta, Arachnoidea, Myriapoda, and Crustacea, are included, 

 and these comprise the following orders : 



Of Insecta ; Hymenoptera, Coleoptera, Lepidoptera, Diptera, 

 Suctoria and Apterygota. 



Of Arachnoidea ; Pseudoscorpionina, Phalangioidea, Araneina, 

 and Acarina. 



Of Myriapoda ; Chilopoda, and Diplopoda. 



Of Crustacea ; Isopoda.f 



* In his list of works consulted, he mentions a paper by L. E. Adams, of 

 Staft'ord, communicated to the Manchester Lit. and Phil. Society (Vol. 47, 1902-3, 

 p. 1-39), but this, on examination, appears to refer entirely to the Natural History 

 of Talpa europaea and to the architecture of their " fortresses," without any 

 allusion whatever to any insects associated with them. 



t We follow the author's classification of Arthropods. 



