96 



DucKETT (A. B.). Notes on a little-known Rabbit Ear-Mite {Psoroptes 

 cuniculi, M^gnin). — Proc. Entrm. Soc. Washington, Washington, 

 B.C., xviii, no. 1, March 1916. p. 17. 



During April 1915, two rabbits used for experimental purposes died 

 from the effects of ear mange, caused by Psoroptes cuniculi, a mite 

 hitherto unrecorded in America. Examination showed cerebral 

 disturbances, the mites having penetrated to within five milHmetres 

 •of the brain. Listrophorus gihhus, Pasquest, a European species of 

 mite, was also observed for the first time on the hair of rabbits. 



TowNSEND (C. H. T.). Non-intentional Dispersal of Muscoid Species by 

 Man, with particular Reference to Tachinid Species.— Proc. Entom. 

 Soc. Washington, Washington, B.C., xviii, no. 1, March 1916, 

 pp. 18-20. 



The conditions necessary for the effective dispersal of insects to new 

 ■countries are (1) the maintenance during transit of the conditions under 

 which a given species normally breeds or fives in either a quiescent or 

 active state, and (2) the presence of the same conditions in the country 

 of introduction. The flies whose larvae normally five in the dung of 

 domestic animals, such as Musca (Promusca) domestica, Stomoxys 

 calcitrans, Lyperosia (Haematobia) irritans, Muscina stahulans, etc., 

 are easily carried to all parts of the world to which cattle and fike 

 animals are shipped, since the required conditions are present. 

 Chrysomyia {Cochliomyia) macellaria, infesting open wounds and fresh 

 carcases, and Cynomyia tnortuorum, inhabiting older carcases, remain 

 confined to America and Europe respectively, since the first require- 

 ment is practically always wanting. In cases in which the larvae are 

 parasitic in insect hosts and remain dormant in the earth in the pupal 

 stage, the second condition is lacking, and even when aided by man, 

 estabfishment is extremely difficult. It is very doubtful whether any 

 of the Tachinids regarded as common to Europe and North America 

 are really so. The existence of a closely similar species in the coimtry 

 of introduction constitutes a bar to establishment, since the foreign 

 species is often swallowed up by the native species through inter- 

 breeding, the issue apparently inheriting the physiological characters 

 of the latter. The identification of species outside their natural 

 faunal limits is therefore of great difficulty and involves a consideration 

 of the principles governing dispersal. 



Banks (N.). The Acarina or Mites. — U.S. Dept. Agric., Washington, 

 B.C., Kept. no. 108, loth December 1915, pp. 153, 294 figs. 

 [Received 8th May 1916.] 



This paper is intended for the use of economic entomologists. The 

 distribution of the various species of Acarina in America is given in 

 detail with keys to all the known American genera. A list of 

 works useful in the study of American Acaiina is appended. 



