ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 31 



particular species harbouring them." It looks ;is if the caeca] bacteria 

 were antagonistic to intruding bacteria. The caeca differ greatly in 

 different types ; they show a gradation from simple to complex forms; 

 they may be indices of relationship. 



Suction in Potato Capsid Bug.* — P. R. Awati has made a thorough 

 study of the mechanism of suction in Lygus pabuhnus. He deals with 

 the mouth-parts and their homologies, the structure of the head, the 

 tentorium, the muscles of the head, the pharynx, gustatory organs, and 

 pumping apparatus which forces the salivary secretion forward into the 

 efferent salivary duct and thence into the ejection-canal of the maxillary 

 stylets. In sucking, the first step is to apply the proboscis to a suitable 

 part of the leaf. The stylets are then driven forwards, being pushed 

 down by the bending of the proboscis. When the stylets reach particular 

 tissues, the maxillo -mandibular muscles begin to act, and the mandibles 

 get fixed into the cellular walls by means of their recurved hooks. 

 Saliva is injected into the wound and probably affects the sap. There is 

 capillarity in the suction-canal and this is helped by the turgidity of the 

 cells. In the pharynx there are two complementary factors which force 

 the sap onwards towards the oesophagus : (1) a vacuum is produced by 

 the raising of the operculum, and (2) the elasticity of the operculum 

 enables it to regain its normal position. A peristalsis is produced in the 

 oesophagus by means of constrictors, and a valvular action prevents the 

 sap from flowing back into the oesophagus from the stomach. 



Injurious Insects in Ireland.f — G. H. Carpenter deals with the 

 frit-fly, larvas of a species of black-fly (Bibio) eating into potato-tubers, 

 the migratory Apple aphid (Aphis fitchii), the Furze mealy-bug (Pseudo- 

 coccus aceris) from apple shoots, various spring-tails (Achorutes armatus 

 and Lipura armata), the fern scale-insect (Chionaspis aspidistrse) from 

 filmy ferns, and many other forms. He reports the interesting occur- 

 rence of the ox warble-maggot (Hypoderma bovis) from the back of a 

 horse. 



Braconid Parasite of Pine-weevil. J— J. W. Munro has found 

 parasitic larvae attacking the larvae of Hylobius abietis, and has identified 

 them with Bracon hylobii Ratzeburg. They may be of value in com- 

 bating the attacks of the pine-weevil, which are becoming more and 

 more common in Britain. It is a hardy parasite, apparently without 

 hyperparasites, and it attacks the weevil larva in its resting stage. 



Life-history of Belladonna Leaf-miner.§ — A. E. Cameron describes 

 the various stages of Pegomyia hyoscyami — egg, larva, and pupuium, 

 and deals also with the copulation, oviposition, and the embryonic 

 period. Special attention is paid to the buccal-pharyngeal apparatus 

 and to practical questions. The maggot devours the parenchyma of 



* Proc. Zool. Soc, 1914, pp. 685-733 (29 figs.). 



t Econ. Proc. R. Dublin Soc, ii. (1914) pp. 142-60 (1 pi. and 8 figs.). 



t Ann. Applied Biol., i. (1914) pp. 170-6 (4 figs.). 



§ Ann. Applied Biol., i. (1914) pp. 43-76 (2 pis.). 



