173 



Hase (A.). Neue Beobachtungen iiber das Leben der Bettwanze 



(Cimex lectularius, L.). [New Observations on the Life of the 

 Bed-Bug.] — Centralbl. Bakt., Parasit. u. Infektionskrankk., Ite. 

 Abt. Orig., Jena, Ixxxiii, no. 1, 8th April 1919, pp. 22-39, 25 figs. 



Eggs are laid by Cimex lectularius for some time after the bug has 

 begun fasting. At a temperature of 94°-99° F. (35°-37° C.) none 

 are laid after 7 days, which period increases- to 12 days at 71°-78° F. 

 (22°-26° C.) and to 27 days at 59°-65° F. (15°-18° C). Up to 23 

 eggs have been laid by a single fasting female. Under optimum 

 conditions a large number of eggs were laid by young females that 

 had been fertilised once ; the maximum nmnber of 153 eggs was 

 laid in 36 days, during which period feeding was permitted every 

 3 or 4 days. The largest number of eggs laid in 24 hours was 12. 

 The maximum number of eggs laid by one female during her entire 

 life-time was 250, but it is thought that this figure may be exceeded. 

 Virgin females can only lay imperfect eggs. Fertihsed females lay 

 both imperfect and normal eggs ; the imperfect eggs are laid prior 

 to fertilisation or when the supply of .spermatozoa is exhausted. 

 In the latter case a fresh fertilisation results in normal eggs being laid. 

 The eggs are laid singly, in heaps, and in rows. The duration of the 

 larval period is shortened to 27 days by abundant food and an optimum 

 temperature of about 85° F. (30° C). Moulting may be delayed for 

 months if one of these factors is lacking. A still shorter larval period 

 may be possible. The males are more numerous than the females ; in 

 bred specimens the proportion was 110 to 100 and in captured ones 

 128 to 100. The more marked difference in the latter case may be 

 explained by the greater ability displayed by the females in evading 

 capture. 



As regards the rapidity with which buildings become infested 

 it is clear that it will be most marked in summer, in rooms that are 

 used both for cooking and sleeping, and in places where the bedding 

 is always warm owing to being constantly occupied. From the 

 practical point of view it is very necessary that measures against 

 C. lectularius should be applied as early as possible after its j^resence 

 is ascertained. 



Eckstein (F.). Zur Systematik der einheimischen StechmUcken. 

 2. Vorlaufige Mitteilung : Die Larven. [A Contribution to the 

 Systematic Study of Mosquitos native to Germany. Second 

 Preliminary Communication : The Larvae.] — Centralbl. Bakt. 

 Parasit. u. Infektionskrankk., Ite. Abt. Grig., Jena, Ixxxiii, no. 3, 

 30th June 1919, pp. 281-294, 18 figs. 



The first of these papers [see this Review, Ser. B, vii, p. 69] reviewed 

 the classification of German mosquitos and dealt with the females. 

 The larvae form the subject of the present paper, which contains 

 a key to the species with brief notes on each. 



Steel (T.). The External Parasites of the Dingo {Canis dingo, Blum.). 

 — Proc. Lin. Soc. N.S.W., Sydney, xliv, no. 173, part 1, 

 27th June 1919, p. 93. [Received 5th September 1919.] 

 Parasites taken from a dingo in 1883 in New South Wales have 



recently been identified as the fleas, Ctenocephalus felis and C. canis. 



