467 



Keiltn (D.) & Thompson (W.R.)- Sur le Cycle evolutif des Dryinidae, 

 Hymenopteres parasites des Hemipteres homopteres. [On the 

 evolutive cycle of Dryinidae, Ilymenoptera parasitising Homop- 

 tera.] — C. R. Soc. Biol., Paris, Ixxviii, no. 5, IQth March 1915, 

 pp. 83-87, 10 figs. 



The Dryixidae dealt with in this paper are all parasitic on Homop- 

 tera, such as Fulgorids, and especially Jassids. The material used for 

 these observations consisted of TypMocyba sp. collected in the Luxem- 

 bourg gardens in Paris, specimens of Tlmmnoteiiix from Cambridge, 

 and some Jassids from Ceylon ; the detailed description of the young 

 larval stages applies to the larvae found in Typhlocyha sp. In the 

 earliest stage, which is said to be strictly embryonic, the parasite is 

 found in the interior of its host, affixed to the inner wall o^ the first 

 abdominal segments and enveloped in a sort of cyst, through the walls 

 of which all its nutriment must pass. When the larva is developed, 

 it penetrates between the first two abdominal segments, producing 

 an external hernia. This never takes place in Typhlocyha until after 

 the second moult. As the growth of the parasite proceeds, the 

 Typhlocyba becomes more and more sluggish. Just before the larval 

 parasite detaches itself from the host, it alters its mode of feeding, 

 and devours the whole of the internal organs ; it then falls to the 

 ground, pupates and remains in this state until spring. The anatomy 

 of the larva in its various stages is described in detail. 



Pratt (H. C). The Malayan Locust (Pachytylus sp.) — Dept. Agric. 



Fed. Malay States, Kuala Lumpur, Bull. no. 24, 1915, 42 pp., / 



3 figs., 16 plates, 1 map. 



The locust has probably been imported into Malaya, where the life- 

 cycle occupies from 100-140 days. The breeding grounds are 

 scattered. There is a general periodicity in the abundance of hoppers 

 and adidts, but the different stages can often be found in the same 

 district at the same time. The young forms feed mainly on wild 

 grasses, when these are abundant ; rice and coconuts are also attacked. 

 IHigration begins two or three days after emergence, and it seems 

 probable that the direction followed is not entirely due to chmatic 

 conditions. Natural enemies have not so far been of any material 

 use in reducing the number of locusts. A few predatory Hymenoptera 

 are kno\^Ti, mainly attacking the hoppers, such as : — Vespa cincta, 

 Polistes Sagittarius, Camponotus sp. and Oecophylla smaragdina. 

 Uninterrupted rain has a marked effect on the number of eggs and 

 fliers. In the Malay States, very httle success has been achieved by 

 the collection of eggs or their destruction by ploughing or hoeing. The 

 three methods used against the hoppers are the driving and pit system, 

 poisoning and netting. The chief difficulty in the pit method lies in 

 the fact that, in many cases, the swarm is not sufficiently concentrated. 

 Easily portable traps consisting of canvas, have been devised and do 

 away with the necessity of digging ditches. The danger of changing 

 the direction of advance, due to digging a short distance in front of 

 a swarm, is thus avoided. The most effective stomach poison, as 

 shown by a series of spraying experiments, is sodium arsenite. If 

 this is used, measures must be taken to prevent cattle, etc., from feeding 



(C180) d2 



