NO. 7 PROTECTIVE ADAPTATIONS McATEE 95 



stomachs (485) examined by him, and Mitchell and Pierce record 

 the extermination of a colony of these ants by horned-toads. Several 

 species of snakes and a few turtles feed to a slight extent upon 

 Hymenoptera. 



Among mammals, moles prey extensively upon ants, and shrews 

 and bats by no means avoid them. In our country armadillos are 

 destructive ant eaters and in other continents various mammals 

 specialize upon ants. Spermophiles and other slightly insectivorous 

 rodents include ants and other Hymenoptera in their Ijill-of-fare. 

 Skunks are assiduous in digging out the nests of yellowjackets (J^es- 

 piila), the comb, its contents and active inhabitants of the nest all 

 being devoured. IMice, weasels, foxes, and especially badgers simi- 

 larly ravage the nests of bumble bees, while bears plunder not only 

 these insects but also honey bees and hornets. Meadow mice and 

 shrews have been found to be among the most effective enemies of 

 sawflies, extracting the larvae from the cocoons, and these and deer 

 mice take a heavy toll of the Hessian fly, nibbling the stem-galls and 

 devouring their inmates. Squirrels feed freely upon galls produced 

 by Hymenoptera. 



The insect enemies of Hymenoptera are numerous and effective and 

 strangely enough many of them are within the ranks of the order. 

 Philanthidae use Aculeates for food, many bees, cuckoo wasps, and 

 the like live parasitically in the nests of other Hymenoptera; the 

 surprising phenomena of liyper-parasitism reveal numerous serious 

 enemies of Hymenoptera among their own kin ; and a number of 

 dipterous parasites of sawflies. bees, and wasps are known. The 

 so-called guests in the nests of bees and ants destroy many of the 

 larvae of their hosts. Predacious insects such as assassin bugs, Phy- 

 matidae, dragonflies. and robber flies feed freely upon Hymenoptera. 

 the last-named foes almost appearing to have a preference for the 

 larger and better armed sorts of stinging Hymenn])tera. Spiders of 

 certain species entrap and devour large numbers of Plymenoptera. 

 Nematode and protozoan parasites exist and some Hymenoptera have 

 important fungal and liacterial diseases. 



Discission. — According to selectionists, Hymenoptera are the most 

 highly protected insects and the so-called mimicry of examples of this 

 order, such as the ants, by numerous spiders, long-horned beetles and 

 rove beetles, plant-bugs, and other insects is regarded as strong 

 evidence for the truth of the claim. Let the case be presented in the 

 words of an advocate fPoulton, Essays on evolution, p. 260-261, 

 1908) : " The means l)y which the resemblance to ants is brought about 

 are diverse, the end — the resemblance itself — is uniform. Further- 

 7 



