158 ARACHNIDS AND MYRIAPODS 



Berlese (1912) has reared what he considers to be the Acarus 

 muscarum of Linnaeus from the Stable-ily, Muscina stabulans, 

 and finds that the adult belongs to the genus Histiostoma. He 

 also illustrates two Acarids attached to M. domestica ; attached to 

 the right anterior tibia is a larval Trombidium and attached to the 

 left hind tibia is a migratory Holostaspis marginatus Herm., a 

 species which is accustomed to attach itself to coprophagous 

 insects. 



By tlie transference of the hypopal or migi'atorial stage of 

 those species of mites which are destructive to cheese and other 

 foods, house-flies are frequently responsible for infecting such foods 

 with mites. While their food is abundant the adult mites re- 

 produce rapidly, the 3'oung mites developing into adults in a very 

 short time. Should the food supply become exhausted or other 

 unfavourable conditions supervene the almost fully grown mites 

 develop the hard protective shells characteristic of the hypopal or 

 migi'atorial stage. Thus protected they attach themselves to 

 house-flies or other flies and trust that the inquisitive wanderings 

 of their transporting host will carry them to pastures new. 



Centipedes and Spiders. 



The carnivorous habits of the centipedes are well-known but 

 the peculiar genus Scutigera contains a number of species which 

 feed upon insects, including the house-fly, when the opportunity 

 occurs. 



In the southern and eastern regions of the United States a 

 species, Scutigera forceps Raf , occurs very frequently in houses 

 where, according to Howard, its food consists principally of house- 

 hold insects such as M. domestica, clothes moths and small cock- 

 roaches. It is a small fi-agile-looking animal with unusually long 

 legs and feeds at night, its long legs apparently being of gi-eat 

 service to it in capturing its prey. 



Kunckel d'Herculais (1911) records the occurrence oi Scutigera 

 coleojjtera L. in France Avhere it occurred especially in privies, 

 hunting flies by night, its chief prey being the latrine fly Fannia 

 scularis, which breeds abundantly in such places (see p. 193). 



The genus Scutigera is very widely distributed, S. smithii 



