234 



heat and one killed by cold. Becker has observed in the Ozarks that 

 in the case of Laphygina fnigiperda, S. and A., the phenomena of the 

 year were reproduced day by day, there being two periods of activity 

 a-nd two of inactivity on hot days, and in different canyons in Arizona 

 the differing climatic conditions have a most marked effect not only 

 on the wild cotton but on the weevils ; in some, the weevils have two 

 rest periods in the year and in others they rest from autumn till the 

 following summer. The author proposes to use a long list of technical 

 terms derived from the Greek in connection with this subject, but their 

 general adoption is improbable. The proper correlation of temperature 

 and humidity as affecting the life processes of a given insect should 

 lead to more accurate procedure in the methods of control, e.g., in the 

 date of planting winter crops to avoid damage by the fall army worm 

 {Lajphyginafrugi'perda). 



SwAiNE (J. M.). A New Species of Pityogenes.—New York Sta. Coll. 

 Forestry, Syracuse, Technical Publication no. 2, xvi, no. 1, 

 November 1915, pp. 8-10. [Received 11th April 1916.] 



A description is given of Pityogenes hopkinsi, sp. n., a Scolytid beetle 

 found in pines throughout the eastern part of Canada and the United 

 States. 



Blackman (M. W.). Observations on the Life-History and Habits of 



Pityogenes hopkinsi, Swaine. — New York Sta. Coll. Forestry, 

 Syracuse, Technical Publication no. 2, xvi, no. 1, November 1915, 

 pp. 11-66, 6 plates. [Received 11th April 1916.] 



Pityogenes hopkinsi, Swaine, a Scolytid beetle boring into the bark 

 of pine in eastern Canada and the United States, hibernates in the 

 burrows in the larval, pupal or adult condition. The young larvae 

 burrow entirely in the bark, only entering the sap-wood when nearly 

 half grown and for purposes of hibernation. The pupal chamber and 

 the hibernating and feeding chambers of the adult occur mainly in the 

 sap-wood. It is probable that the adult may pass the winter in a 

 different host from that in which the larval and pupal stages were 

 spent. The emergence of hibernated adults takes place in the latter 

 part of April, the males appearing before the females. The entrance 

 gallery and the nuptial chamber of the brood burrow are constructed 

 in a new host by the male, the time occupied being from two to six 

 days. The nuptial chamber may be entirely in the bark or the sap- 

 wood, or partly in both. Pairing occurs in the burrows ; egg-laying 

 begins soon afterwards and continues for a period up to 14 days. The 

 incubation period lasts about seven days. The length of larval life 

 varies with temperature and humidity, the average for spring conditions 

 being from 18 to 25 days. The average duration of the pupal period 

 is five or six days. The oSspring of over-wintering adults emerge 

 and attack new hosts in July. Under favourable conditions the adults 

 of the second generation may give rise to a partial third brood in 

 September, the larvae of which hibernate through the winter. 



P. hopkinsi breeds only in thin-barked pine, preferring recently cut 

 or suddenly killed branches, or those which have been weakened by 

 other insects or by fungi. Excessive multipUcation may be prevented 

 by burning waste material after lumbering operations. 



