201 



in 1919, the hinterland of Benghasi being particularly infested. 

 Wheat was severely injured, barley less so, as the drought in 1919 had 

 accelerated ripening. li\ Cyrenaica the eggs of this locust hatch about 

 the end of March on the coast and up to May in high-lying districts. 



Natural enemies include many reptiles and birds. An Acarid 

 belonging to the genus Eutromhidium parasitises the locusts on the 

 plateau, but was not found at the coast. 



A further outbreak may be expected in 1920 and flame-throwers 

 and poisoned bran are recommended as providing the methods best 

 suited to the country. Fire must be used early in spring against 

 the masses of hoppers and nymphs, while poisons are adapted for use 

 in gardens against all stages. These measures against the native 

 generations of Tettigonia albifrons will not dispel all danger, as swarms 

 of locusts of other species may invade the country. Cyrenaica is. 

 however, one of the north African regions that are rarely subject to 

 this danger, probably because it is outside the usual lines of migration. 

 An agreement between Great Britain, France and Italy, as has been 

 suggested before, provides the only way of dealing with the locust 

 problem throughout northern Africa. 



GuERREiRO Beatriz (M.). Rhynchota damaging Cotton in Angola,, 



Portuguese West Africa. — Bol. Agric, Pecudria e Fomento, 



Loanda, 1919, 3rd Series, pp. 64-66. (Abstract in L' Agric. Colon., 



Florence, xiv, no. 1, 31st January 1920, p. 57.) [Received 8th 



March 1920.] 



In October 1918 the cotton plantations at Katete, Angola, were 



invaded by the stainer, Oxycarenus hyalmijiennis, Costa. This 



bug feeds on the seeds and oviposits in the open bolls. To limit the 



injury it is necessary to harvest the cotton without delay and to burn 



all the old bolls left in the fields together with the grasses growing 



near them. 



A Thysanopteron injurious to Cacao in the Island of San Thome, 

 Gulf of Guinea. — Bol. Centro Colonial, Lisbon, xi, 1919, pp. 7-8. 

 (Abstract in V Agric. Colon., Florence, xiv, no. 1, 31st January 

 1920, p. 57-58.) [Received 8th March 1920.] 



The occurrence of Heliothrips rubrocinctus in San Thome has been 

 known for many years, but the infestation has hitherto been so shght 

 as to be unimportant. Recently, however, a violent outbreak took 

 place near the city of S. Thome and many cacao plantations suffered 

 severe losses ; the northern part of the island appears to be less 

 affected. A spray, ■ that has given good results consists of : — Tar 

 14 lb., palm oil 23 lb., wood ashes 23 lb., water 50 gals. 



PiCTET (A.) Recherches experimentales sur I'Adaptation de 

 Lymantria disjpar aux Coniferes et a d'autres Essences. — 



Mitt. Schweiz. Entom. Gesell., Berne, xiii, no. 1, November 1919, 

 pp. 20-54, 1 plate. [Received 11th March 1920.] 



The larvae of most Lepidoptera are usually limited to a few food- 

 plants or even to one only. Porthetria (Lymmitria) dispar (gipsy moth) 

 is one of the exceptions, and in this paper an attempt is made to 

 elucidate the following points : — The adaptation of the caterpillars 



(673) C 



