110 EXTRACTS. 



two being comparatively abundant. The ova of T. dispar 

 appeared able to withstand putrefaction in dead flies for 

 nearly two months. {SJihrore, J. 0., Parasitology, viii. 3, 

 1916). 



Further observations vvere carried out during 1913 by 

 Marchoux to demonstrate the transmission of leprosy by 

 flies. The experiments showed that female flies were found 

 to absorb more septic material than males, and the same 

 material remained alive for a longer period in the intestine 

 of the female. The bacilli could live in the digestive tract 

 for at least four days^ and it is therefore considered probable 

 that infection can take place by the deposition of fiesh 

 excrement on wounds. {Marchou.v, E., Ann. Inst. Pasteur, 

 Paris, XXX. 2, 191d.) 



Insect ailments. — Polyhedral diseases are known to occur 

 naturally in many caterpillars. Several forms of disease 

 can be distinouished, each of which is characterized bv a 

 special type of polyhedra. The size of the polyhedra varies 

 very considerably in different species of insects, but there is 

 a marked similarity in shape. 



Wilt disease of gipsy moths, army worms, etc., is caused 

 by a filterable virus, and it is believed that the polyhedra 

 arise as a renction against the invasion of the virus. The 

 polyhedra are not living organisms. {Glaser, R. W., and 

 Chapman, J. W., Biol. Bull. Marine Biol. Lab. Woods 

 Hole, Mass., U.S.A., xxx. 5, 1916.) 



The di.<ipersal of a Leaf Mite. — It has been supposed that 

 birds, insects, and even tlie wind m;iy be responsible for the 

 distribution of the leaf-blister mite (Eriophy es gossypii), 

 and it has also been believed that transportation from ])lace 

 to place may have been effected on cotton seed. In 1914 

 microscopic observation showed that the full-grown mites 

 had a tendency to ascend to the tips of leaf-hairs and assume 

 what appeared to be a waiting position. When a hair from 

 a camel's hair brush was brought into contact with them, it 

 was immediately gras[)ed and the mite loosened its hold on 

 the leaf-hair and allowed itself to be carried away. A mit© 



