160 



the range was from 75 per cent to 3' 4 per cent. A similar 

 enquiry in South Germany and Saxony showed a maximum of 

 99 per cent and a minimum of 1 per cent, and the total deprecia- 

 tion of value is estimated at £181,705. The following percent- 

 ages of warbled hides are given for the various provinces : 

 Kheinland 35, North Germany 22, Alsace 18, Oldenburg 15, 

 Saxony 8, Baden 2, Bavaria 1, and Wurtemburg 1 per cent. 



The author then goes on to discuss the loss caused by the tly 

 interfering with the nutrition of cattle even some time before 

 any warbles are developed, and also the considerable loss of milk 

 so caused. M. E-asquin puts this at over 29 francs per head of 

 milch cows per annum, which the author thinks is an under- 

 statement. The German Agricultural Journal puts the annual 

 loss from this cause in millions of marks at: — Holland 7, 

 England 120, Germany 90. 



The author then describes Hypoderma lineata, H. bovis, H. 

 equi and H. diana and discusses their bionomics, taking as his 

 authority the report of the German Commission on the warble 

 lly (H. Glaser, ' TJeber Dasselfliegen, Mitteilungen des 

 Ausschusses zur Bekampfuug der Dasselfliege,' no. 2; Berlin, 

 1912), and the various views as to the manner in which the larva 

 reaches the skin of the back are discussed at length. With 

 reference to methods of combating the pest, it is stated that 

 smearing with various tarry and oily lotions in common use is 

 apparently of little avail ; but in those districts in which cattle 

 are put under shelter during the great heat of the day, that is 

 to say from 10 a.m. until 5 p.m., the number of animals warbled 

 is very limited, and possibly this may prove to be a useful pre- 

 ventive measure. The destruction of the larvae systematically 

 carried out is probably the most practical method of combating 

 the pest, and the following figures are given as the result of the 

 application of this method at the Co-operative Dairy of Skjaerum- 

 Molle, with a total head of cattle ranging from 3,800 to 4,000 in 

 the period covered. In 1902, 2,082 milch cows and 1,721 young 

 beasts were examined, at a cost of 403 francs and 96 days work, 

 and 22,394 larvae were killed ; in 1910, 2,219 milch cows and 

 1,338 young beasts were examined at a cost of 133 francs and 

 only 3,875 larvae were killed. A further table shows that the 

 native cattle in 1906 averaged 107 larvae per head, while pur- 

 chased cattle averaged 17"4; and in 1910 the figure was Oil for 

 the native cattle and 16'0 for cattle purchased outside, thus 

 showing that the large amount of labour involved was caused by 

 the imported cattle and that otherwise the owners would have 

 been able practically to suppress the pest locally. 



Bisiiorr (F. C.) & Wood (H. P.). The Biology of some North 

 American Ticks of the Genus Dermacentor. — Parcultolojjjj, 

 vi, no. 2, July 1913, pp. 153-187, 3 pL, 10 tables, 1 map*. 



In North America there are at least eight valid species of the 

 genus Derviacentor and one variety. The species of the genus 

 may be divided into two groups, based on their habit of moulting 

 on or olf the host. The former group comprises D. nitens, 



