464 ANNUAL REPOET SMITHSONIAN INSTITUTION, 1912. 



the present-day Strongylognathus testaceus — the more so as Strongy- 

 lognathiis lives with Teti-amorinm and is to be derived from this 

 same genus. But in the meantime more than conjecturee are not at 

 our command for the phyletic history of Anergates. 



The investigations hitherto made concerning the hypothetical 

 phyletic past of social parasitism and of slavery have in any case 

 led to the recognition that this history forms only an ideal unit, but 

 in reality is composed of a multitude of really distinct lines of de- 

 velopment, which, in different genera and species in the different 

 subfamilies of ants, have begun at different times and up to the 

 ])resent have progressed to different points. The more we succeed^ 

 by means of new observations and experiments, in establishing these 

 separate lines of origin, the more we will also proceed in our general 

 knowledge of phylogenetic connection between parasitism and slavery 

 among the ants. Just as in the morphologico-paleontological domain, 

 so also here a true enrichment of our knowledge is not to be ex- 

 pected from general theoretical reflections, but from critical detailed 

 investigations. 



3.— TRUE MYRMECOPHILY (SYMPHILY). 



While the living together of ants of different species comes under 

 the concept of social symbiosis, their association with nonsocial 

 animals, particularly with other arthropods, is designated as indi- 

 vidual symbiosis. Therefore we are to deal here with the so-called 

 ant guests or myrmecophiles from other families or orders of insects 

 and of the remaining arthropods. The number of normal ant guests 

 in 1894 already amounted to about 1,200; to-day we may estimate them 

 at more than 2,000. Their relations to the ants are very various and 

 maybe divided mto five main classes, which, however, are connected by 

 many transitions. We distinguish symphiles or true guests, synoeketes 

 or indifferently tolerated tenants, synechthrans or actively pursued 

 tenants; furthermore parasites (ento- and ectoparasites), and finally 

 trophobionts or food-producing animals of the ants. I shall here 

 only briefly enter into the first of these classes, because we shall 

 afterwards become acquainted with many an interesting staphylinid 

 in connection with the legionary ants, and particularly for the reason 

 that Mr. Donisthorpe is to deliver a lecture on the indigenous ant 

 guests. 



The true ant guests (symphiles) are hospitably cared for by the 

 ants on account of certain exudations, which are volatile products 

 of the fatty tissues (in the Lomechusini) or of adipoid glandular 

 tissues (Clavigerinse, Paussidae, etc.), while with the physogastric 

 termite guests the blood tissue is the principal exudatmg tissue. The 

 external exudatory organs are very diversely developed; yeUow 

 hair tufts, dermal pores, dermal cavities, etc., at which the hosts lick 



