NO. 7 PROTECTIVE ADAPTATIONS McATEE 23 



instantaneous tai the small animals v/liich form the food of the Centipedes. I 

 have myself watched Lithobius in this country creep up to a blue-bottle fly 

 and seize it between the poison claws. One powerful nip and the blue-bottle 

 was dead, as if struck by lightning. I have also seen them kill worms and also 

 other Lithobius in the same way. Wlien another Lithobius is wounded by the 

 poison claws it seems to be paralyzed behind the wound. The Millepedes, on 

 the other hand, have no such ofifensive and defensive weapon. They rely for 

 protection on the fluid secreted by the stigmata repugnatoria (or glandulac 

 odorijcrae) mentioned before. This fluid has been shown to contain prussic 

 acid, and has a very unpleasant odour. Most of the Millepedes are provided 

 with these glands ; but in the cave Myriapods mentioned before, the animals 

 have not to contend against so many adversaries, and these glands almost 

 disappear. Other Myriapods defend themselves by means of the long and stiff 

 bristles with which they are provided, e. g., the little Polyxenus. 



Bird enemies. — Centipeds have been identified 236 times from the 

 stomachs of 65 species of nearctic birds, and miUipeds 2,598 times 

 from 98 species. The latter were identified more than 50 times in the 

 case of each of 12 species of birds. The highest number of milhpeds 

 found in a single stomach — that of a starling — was 40. More than a 

 tenth of the starling's annual food in the United States consists of 

 millipeds. 



Number of identifications, 2,862 ; percentage of identifications 

 among those of all Arthropoda, 1.3580 ; percentage of species in this 

 class among the whole number of arthropod species known, .4781. 



Other enemies. — A. H. Kirkland in his report on the " Usefulness 

 of the American toad " ^ states that 10 per cent of the food of 149 

 individuals examined consisted of millipeds and that as many as yy 

 were found in a single stomach. Myriapods are eaten also by frogs, 

 salamanders, lizards, snakes and turtles. Among mammals the com- 

 mon mole {Scalopits) , armadillo {Tatii) and civetcat (Bassariscns) 

 (and the mongoose as introduced into Trinidad) are known to feed 

 on centipeds, and Brewer's mole (Parascalops) and the armadillo on 

 millipeds ; shrews prey upon both groups. Centipeds are eaten by 

 predacious beetles, frequently prey upon each other, and it appears 

 that often the male is consumed by the female following pairing. 

 Millipeds are the chief food also of certain Lampyrid larvae, are 

 eaten by ground beetles, and are parasitized by phorid flies. 



Discussion. — There is a more or less prevalent belief that myriapods 

 are " specially protected " animals. This idea is reflected in an article 

 on " The hothouse milliped as a new genus," in which the author. 



^ Farmers' Bull. 196, U. S. Dep. Agr., 16 pp., 1904. 



