Wasps, Bees, and Ants 553 
of safe transportation due to the migrating habits of many 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 Phoridse, the females of which have become 
extremely degenerate because of their myrmecophilous life. (After Wheeler; 
much enlarged.) 
which the families Staphylinidae (rove-beetles), Pselaphidae, Paussidae, Clavi- 
geridae, Histeridae, Silphidae, Thorictidae, Lathridictidae, and Scydmaenidae 
make up all but 100 species, these latter representing 22 
other families; 76 are Hemiptera, of which 15 are plant- 
lice and scale-insects; 39 are Hymenoptera, of which 22 
are other ant species; 26 are Lepidopterous larvae, 20 
are Thysanura, 18 Diptera, 7 Orthoptera, 1 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, Pselaphid, and 
other beetles, live truly symbiotically 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? 75 8 )? i* 1 adaptation to this extraordinary 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.—Larva of a 
Phorid fly attached 
to the larva of the 
ant, Pachycondyla 
harp ax. (After 
Wheeler; much en¬ 
larged.) 
