ECONOMIC ZOOLOGY — ENTOMOLOGY. 553 



and its relation to other species of coprophagous flies. The investigations show 

 the larvae of H. dentipes, which become predaceous upon reaching the third 

 stage, to be vei-y destructive to the larvse of the house fly and stable fly. 



In experiments to determine the relations existing between the larvae of 

 H. dentipes and those of PoJyetes abolineata, which are the most rapacious of 

 all coprophagous larvre, it was found that the resistance of the former was 

 usually fierce and persistent, but never successful. The larvaj of //. dentipes 

 were never observed to attack each other even when their food was scarce, 

 although such cannibalism is often practiced by larva of Myospila meditabunda 

 and P. albolincata. II. dentipes is very prolific, depositing 170 to 200 eggs 

 which mature at about the same time. The larvje travel very rapidly, are om- 

 niverous feeders, and will live on all materials which serve as breeding places 

 for the house fly. It is said that II. dentipes visits human dwellings. In ob- 

 servations in the district of Tzarskole Selo, the author found no larvje of the 

 stable fly and but few of the house fly, but the larvae of II. dentipes were al- 

 ways abundant. In his opinion II. dentipes, in addition to other parasitic 

 insects, is chiefly instrumental in preventing the multiplication of Musca do- 

 mestica which otherwise would become a great pest. 



Observations of the insect fauna of the southern part of the Government of 

 Stavropol (North Caucasus), made during July and August, 1911, are described. 



Empusa muscae as a carrier of bacterial infection from, the house fly, 

 E. M. Buchanan (Brit. Med. Jour., No. 2760 {1913), pp. 1369-1372, pU. 2, 

 figs. 6). — The author finds that when house flies, parasitized by the fungus 

 E. muscw, are collected on fly paper that they become a center from which the 

 spores of the fungus are showered in numbers sufficient to whiten other flies 

 stuck fast on the paper in close proximity. He reports investigations made 

 with a view to determining whether or not the spores carry with them bac- 

 teria from the body of the fly, if infective organisms from the interior of the 

 fly are disseminated in this manner. 



Though the manner in which the fungus gains entrance to the body of the 

 fly is not definitely known, it has usually been stated as occurring through 

 the germination of a siiore that has become attached to the surface of the in- 

 sect and the penetration of the resulting hyphal filament through the body 

 wall. Flies examined by the author, however, gave no microscopical evidence 

 in support of this view as to entrance through the abdominal and thoracic 

 walls. The fungus permeates the entire body, even the legs and antennae, 

 but in doing so it has always presented certain definite characteristics of lo- 

 calization and form, as are described by the author. The majority of the flies 

 presented great numbers of bacteria in the intestines, and among the hyphae 

 of the abdominal cavity they were widely distributed, spreading toward the 

 abdominal wall. Though the manner in which this fungus persists from 

 year to year is not known, the formation of resting spores would serve to ex- 

 plain this hiatus in the life history of the fungus, but the existence of such 

 bodies has not yet been definitely determined. On the other hand, the author 

 found upon examination of the eggs from a diseased fly that some of the 

 mycelium remained firmly attached to the outer covering or chorion. Thus 

 the deposition of eggs by a fly harboring the fungus renders it extremely likely 

 that the larvae would in turn become infected. 



In order to determine whether the conidia in their outward course carry bac- 

 teria from the fly to the surface upon which they are projected, 10 flies were 

 fixed head downward upon nutritive agar in the center of a Petri plate, with 

 the uniform production of a zonal crop of colonies. Detailed examinations of 

 the first five plated showed that the colonies numbered from TO to 400 and that 

 their distribution was well within the farthest range of the conidia. By the 



