223 



Ransom (B. H.). The Life-History of HaJironenid niim-nc (Carter), 

 a Parasite of the Horse transmitted by the House-Fly.- -T'-N. 



Ihpl. Aiiric. Bitrcdii ofAniiiudlndustrij, Waduuytoii , Bull. 



Hi;;, VdV\, '\(\ ])])., 41 fig-s. 



This is an account of the life liistory of a Nematode worm 

 wliicli infests horses. The embryos of the worms are thrown out 

 with the alimentary dejecta, and enter the bodies of fly larvae 

 whicli liave hatched from egg's laid on tlie dejecta by hoiise- 

 tiies {Musca domestica). The young worms grow in the fly 

 larvae and reach their final stage at aboul^ the time the flies 

 emerge in the winged state. In the flies the parasites are com- 

 monly found in the head, and frequently in the proboscds, but 

 thev also occur in the alimentary canal, and in the thorax. 



KxAi; (F.). Changes in the Mosquito Fauna of Panama. — /Vor. 

 Eiifoiii. Soc, ll'V/.v//., ]Vasliiii(/lon, XV, no. I, 191o, \^\). 40-4;'). 



44ie cluinges in the physical features of the region of the 

 Panama Canal will, as has often been pointed out, bring about 

 (4ianges in the fauna of that zone. There are even now data 

 to show that such (4ianges have already occurred. In working- 

 over the mosquito material from the Canal Zone collected in 1907, 

 the absence of the species Maiisonin fifiJhins was very marked, as 

 it is elsewhere very plentiful. It would seem that the creation 

 of Gatun Lake has since been a cause of its introduction into 

 that neighbourhood. The sam(> is the case with Aedomyin 

 squainipennis. Both these insects, whi(4i are now plentiful in 

 the Canal Zone, are associated with the aquatic plant Pisfin, in 

 their larval stages. This plant grows in shallow water with its 

 leav(>s floating on the surface, and the Mam^nnia larvae are 

 attached to its roots; but how the Acdomyia is attached is not 

 known. 



In discussing this paper Mr. Busck said that many mosquitos 

 and other insects have been eradicated from the Canal Zone 

 owing to the improvements in sanitation, etc. That the opjiosite 

 should have occurred in the case of the above-mentioned species 

 is attributed to the introduction and increase of the plant Pisf/ia, 

 and in combating them it will probably be necessary to destroy 

 the floating islands of this plant. 



TEACi.ARDii (I.). On the Chemotropism of Insects and its Significance 

 for Economic Entomology. — JJull. Eniovi. I'cscavah, London, 

 iv, pt. 2, Sept. 10 1;;, pp. 113-117. 



By ' chemotropism ' is meant a guiding force perceived by an 

 animal through its olfactory sense. It is an important factor in the 

 life of insects, and is especially so in the three following circum- 

 stances : (1) In the search of the sexes for each other; (2) in the 

 search for food ; and (3) in ovipositing. It is a matter of common 

 knowdedge that the males in ceriain six-cies of nu)ths seek out the 

 females from a great distance. In 1910 Verschalfelt published 

 32720 -A- 2 



