PERSECUTED AND TOLERATED GUESTS. 



379 



fully appreciated, owing to the investigations of Wasmann, Janet, 

 Escherich, Reitter, Hamilton, Schwarz, Viehmeyer and others. Was- 

 mann alone, in a series of more than a hundred and fifty papers, may 

 be said to have contributed as much as all other authors to our knowl- 

 edge of these remarkable insects. 



The number and diversity of myrmecophilous arthropods are almost 

 incredible. In 1894 Wasmann enumerated 1,246 species. This list 

 comprises 1,177 insects, 60 Arachnida and 9 Crustacea. Of the insects 

 993 are Coleoptera (283 Staphylinidse, 117 Pselaphidse, 90 Clavigeridae, 



FIG. 224. Synechthran and synoekete Staphylinids. (Original.) A, Myrmedonia 



fimesta; B, Dinarda dentata. 



169 Paussidas, 43 Thorictidse, 128 Histeridae, etc.). Since 1894 many 

 additional species have been brought to light, so that the total number 

 now known is at least 1,500, including fully 1,000 beetles. These, how- 

 ever, represent only a portion of the existing myrmecophilous fauna of 

 the world. Wasmann's and Escherich's estimate of 3,000 species is 

 probably below rather than above the total number that will be recorded 

 when the ant-nests of the tropics and many other regions have been 

 as carefully searched for these insects as those of Europe, 



The existence of this great number of myrmecophiles can be accounted 

 for only on the supposition that ant-nests have a strong attraction for 

 terrestrial arthropods. It is not difficult to understand how this can 

 be the case since, in the first place, the nests are usually permanent 

 abodes inhabited for months or years by successive broods of^ants. 

 Second, these nests have at all seasons a slightly higher temperature 

 than the surrounding soil. Third, there is usually more or less refuse 

 food or offal, pupal exuviae and dead ants, at least in the superficial 



