Wasps, Bees, and Ants 



553 



of safe transportation due to the migrating habits of majiy of their host 

 species. 



The myrmecophilous (ant's-nest-inhabiting) insects are limited to no 

 single order. Of the total of 1177 insect species recorded by Wasmann 

 in 1900 as living for part or all of their life in ants' nests, 993 are beetles, of 



Fig. 758. — Ant-guests; at left, Psyllomyia testacea, female; next at right, Ecitomyia 

 wheeleri, female; at extreme right, male of last-named species. These two insects 

 are species of flies of the family Phoridae, the females of which have become 

 extremely degenerate because of their myrmecophilous life. (After Wheeler; 

 much enlarged.) 



which the families Staphylinidas (rove-beetles), Pselaphidas, Paussida;, Clavi- 



geridae, Histerida;, Silphida;, Thorictida, Lathridictidae, and Scydmasnidae 



make up all but 100 species, these latter representing 22 



other families; 76 are Hemiptera, of which 15 are plant- 



hce and scale-insects; 39 are Hymenoptera, of which 22 



are other ant species; 26 are Lepidopterous larvae, 20 



are Thysanura, 18 Diptera, 7 Orthoptera, i a Pseudo- 



Neuropteron, 34 are mites, 26 are spiders, and 9 are 



isopod crustaceans. While most of these only derive 



advantage from this commensalism with ants, some, and 



notably the small Paussid, Clavigerid, Pseiaphid, and 



other beetles, live truly s\Tnbiotically with their hosts, 



— being of immediate reciprocal benefit to them. 



These little beetles, many of which show most amazing 



modifications of body structure (Figs. 755, 756) (such 



modifications, usually degenerative, are displayed also by 



numerous other ant guests, particularly Phorid flies (Figs. 



757> 758)1 in adaptation to this extraordinar)' life, 



secrete a sweet substance which is greedily eaten by 



the ants. The hosts in return care for, clean, and feed 



by regurgitation the curious little beetles. 



The "wonderful" and "marvelous" character of the behavior of the 



Fig. 759. — Lars'a of a 

 Phorid fly attached 

 to the larva of the 

 ant, Pachycondyla 

 liar pax. (.After 

 Wheeler; much en- 

 larged.) 



