62 EXPERIMENT STATION RECORD. 



tery. and other endemic diseases, and that it also possesses importance as a 

 disseminator of the bacilli of tuberculosis. Studies that have been made of 

 the breeding habits of this fly are reviewed at some length, as is the spread 

 of malaria in C4reece and its relation to the rise and fall of national power. 



The typhoid fly or house fly, L. O. Howard (Bci. Amer. Sup., 67 {1909), 

 No. J7.3'J. pp. 21. 'i, 215). — This is an extract from the bulletin noted above. 



House fleas, L. O. Howard {TJ. S. Dept. Agr., Bur. Ext. Circ. JOS, pp. J,, figs. 

 2). — This is a brief account of house fleas, accompanied by directions for deal- 

 ing with them. The dog and cat flea {Ctenoccphalus cams) is said to have 

 been more frequently i-eported as infesting liouses in this country than the 

 human flea PuJcx irrifans. 



Sixth annual report of the State entomologist of Montana, R. A. Cooley 

 (Montana Sta. Bui. 15, pp. SD-112, pis. 2, fig. ]). — The author here presents a 

 preliminary report of investigations concerning the life history and habits of 

 the tick (Dcnnacentor venustus) that is the active agent iu the transmission 

 of Rocky ^ilountain spotted fever of man in jNIontana and neighborhood States, 

 together with brief notes on Glover's silk moth. 



An engorged female tick collected iu late July which commenced oviposition 

 on August 4 had deposited 4,814 eggs by September 9, a total of 4,820 eggs 

 being laid. These eggs began to hatch on September 30, thus apparently having 

 required 57 days for incubation at the laboratory temperature. Seed ticks 

 which hatched in early July were kept in a stender dish. These commenced to 

 die iu the early part of August, all being dead on August 14, a longevity period 

 of nearly 6 weeks. 



The author concludes that larvfe do not attach to a host until about a week 

 has past after hatching. Larvje engorged upon guinea pigs commenced to drop 

 on the third day following engorgement, the last leaving the host on the 

 seventh day. This variation in the period required for engorgement may be 

 explained bj* the fact that some seed ticks do not attach until long after others 

 have done so. The author's observations indicate that the greater number of 

 larvfe drop during the day. 



Records of the molting of larvse show 13 days to have been the minimum 

 period with about 2 weeks as the average. The period required for engorge- 

 ment in the nymphal stage was from 4 to 8 days. Engorged nymphs that 

 dropped on August 12, molted after periods of 41 to 47 days. 



In order to investigate the host relations of this tick a trip was made into 

 West Gallatin Canyon. During the trip numerous small mammals of 5 differ- 

 ent species were shot. All of 6 Rocky Mountain pikas {Lagomys prince ps) 

 and 2 of 12 chipmunks [Tamias quadrivittatus ainconus) collected had ticks iu 

 the larval or nymphal stages attached in or very close to the ears. 



"It was noticeable that though we shot more red squirrels than other animals, 

 we found no ticks upon them, and though chipmunks were very abundant in the 

 immediate vicinity of the series of rock slides where we secured the pikas, 

 those obtained at this place were in every instance free from ticks, though the 

 pikas had them iu every case." Projects for future work are appended to this 

 acccount. 



Brief notes are given on Glover's silk moth (Samia glovcri) a species fi"e- 

 quently received at the station. While not a pest of much importance, it has 

 been reported as feeding on the currant and gooseberry. Larvfe bred at the 

 laboratory refused to feed on these plants, but willow and maple were eaten 

 freely. Eggs laid on July 5 hatched July 23. Technical descriptions are pre- 

 sented of the six larval iustars. 



