362 EXPERIMENT STATION RECORD. [Vol.38 



from the moths which emerged on that date hatched in 1915 and 1916 and will 

 know approximately when to expect the first larvae in his orchard. 



In the second table are shown the dates when the larvae of the first genera- 

 tion left the apple and the date when the first larvae descending from them 

 hatched out in 1915 and 1916. By banding a dozen or more trees not later than 

 June 1 and examining the bands daily or at intervals of three or four days and 

 consulting the table when larvae are found, the fruit gi-ower may be advised be- 

 forehand when and in what relative numbers the larvae of the second generation 

 will be hatching in the orchard long enough beforehand to protect the crop. 



Syrphidpe of Maine. — II, Life history studies, C. L. Metcalf {Maine Sta. 

 Bui. 26S {1017), pp. 153-176, pis. 5). — In this continuation of the studies pre- 

 viously noted (E. S. R., 36, p. 460) the author reports upon the biology and 

 economic status of four additional species, all of which are aphidophagous. The 

 species considered are Xantho gramma divisa, Syrphus oronoensis n. sp., 

 Platychirus perpallidus, and S. knabi. S. oronoensis appears to be an important 

 predator of aphids affecting stone fruits, X. divisa and S. knabi are, so far as 

 observed, of more benefit to certain shade and forest trees, while the chosen food 

 of P. perpallidus has not been determined. The latter species is of faunistic 

 Interest, since it has not hitherto been recorded outside of Great Britain. The 

 author has also obtained several European species of Platychirus in Maine, 

 namely, P. scutatus, P. immarginatus, P. discimanus, and P. angustatus. 



Attention is called to the fact that Platychirus and Xanthogramma, previously 

 recorded as having species which are scavengers in the larval stage, should be 

 added to the list of ten genera given in the bulletin, previously noted, as aphido- 

 phagous, at least in part. 



"El torsalo" (Dermatobia cyaniventris), J. M. Arias G. {El Tdrsalo {Der- 

 matobia cyaniventris). San Jose, Costa Rica: Dept. Agr., 1917, pp. 19, figs. 6). — 

 An account of this oestrid, called " el torsalo " by the author, the larvae of 

 which develop in the skin of man, in tropical America. 



Studies upon the common house fly (Musca domestica), I, II, J. R. Scott 

 {.Jour. Med. Research, 37 {1917), No. 1, pp. 101-119, 121-124) .—Two studies are 

 reported. 



I. A general study of the bacteriology of the house fly in the District of 

 Columbia. — This is a detailed report upon the bacterial flora of house flies 

 collected in various sections of the city of Washington. 



" House flies show seasonal variation in the number of bacteria carried as 

 well as in the species of bacteria. The seasonal variation shows the greatest 

 bacterial flora is coincident with the summer months, and the occurrence of 

 intestinal complaints of summer and early autumn. The isolation of members 

 of the colon-typhoid-dysentery group of bacilli from numbers of flies indicates 

 that the house fly has the power of carrying the closely allied pathogens, 

 typhoid and dysentery. The finding of rirulent pyogenic cocci indicates the 

 possibility of the common house fly being a factor in the dissemination of the 

 suppurative processes. 



" The results of my experiments indicate that typhoid fever in the District of 

 Columbia, under normal conditions, is not referable to the agency of the house 

 fly." 



II. The isolation of B. cuniculicida, a hitherto unreported isolation. — In 

 the course of the investigations above noted, the causative organism {Bacillus 

 cuniculicida) of a septicemia in rabbits and guinea pigs was obtained from 

 two flies. This appears to be the first reported instance of its isolation from 

 the house fly. 



" This recovery of B. cuniculicida may indicate at least one manner in which 

 the bacillus is carried to pens of healthy experimental animals, and demon- 



