Worms Schistocephalus solidus

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WORMS SCHISTOCEPHALUS SOLIDUS, Müller. solidus is a tapeworm of fish-eating birds and has a somewhat complex life history. T h e egg falls into the water with the faeces of the bird-host and soon releases a ciliated embryo or coracidium.

If this is swallowed by a " water-flea " it makes its way into the tissues of its host and there develops into a stage called a procercoid.

When the water flea is eaten by a fish, usually a stickleback, the procercoid makes its way through the wall of the fish's intestine into the body cavity where it develops into a plerocercoid, a flat white fluke-like creature about ^-in. long and J-in. across. U p to ten of these have been found in a single stickleback and even a smaller number can make it difficult for the fish to swim so that it is more easily caught and eaten by a bird. When the infested fish is swallowed by a bird the plerocercoid develops into the adult worm in the bird's intestine, to the walls of which it attaches itself like other tapeworms, by suckers and hooks.

J. D. Smyth has shown (Journal of Experimental Biology, 1946) that the plerocercoid larvae of S. solidus mature rapidly when cultured aseptically in suitable media at a temperature of 40° C., the average body temperature of a bird, and more recently (loc. cit. 1952) that when cultured at 30° C., the worms do not mature.

If, therefore, an infested stickleback is eaten by another fish the plerocercoids, not being raised to the necessary temperature, do not develop into the adult tapeworm and cannot, therefore, attach themselves to the intestinal wall of their new host. They can, however, resist the action of the digestive juices—as they would in any case have to resist those of a bird—remain alive in the fish's alimentary canal and are presumably eventually voided with the fish's faeces, still alive. No one so far as I know, has fed an infested stickleback to a predaceous tropical fish—if such there be—that normally lives in water at a temperature of 40° C. S. solidus has not so far been recorded from Suffolk either in the adult form from a bird or as a plerocercoid from a stickleback : it is probably not uncommon and well worth looking for.

C.

B I R D PARASITES. N E W to Suffolk. T h e worms Choatonaenia infundibulum, Block, in Red Legged Partridge and Porrocaecum depressum, Zeder, in Kestrel are recorded from Suffolk by Dr. A. H. Bayles in Ann. & Mag. Natural History I, 10 (1928).

H.

C.

GRANT.

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WORMS

T R I A E N O P H O R U S NODULOSUS, (Pallas) is a well-known parasite of pike, though there are very few records of its occurrence in this country. T h e first larval stage of this species of tapeworm occurs in water-fleas, principally Cyclops. T h e second stage, the plerocercoid, forms subperitoneal cysts, particularly on the liver, in various cyprinid fishes. When fishes infested with the plerocercoids are eaten by pike, the vvorms develop to the adult stage, usually in the intestine. C.

NOTES ON BRITISH LEPIDOPTERA FOR 1952 B Y BARON DE W O R M S , M . A . ,

PH.D.,

F.R.E.S.

I HAVE thought it might be of interest to put on record a resume of the past season, 1952, so far as our lepidoptera are concerned so as to give some idea of the relative abundance of various species and also the general trend of the year which rray be Said to have opened with quite an eclat. Düring the last days of February a few Painted Ladies (Pyrameis cardni, Linn.) appeared on the south coast to be reinforced by an almost unprecedented immigration of these butterflies during the first days of March. Hundreds were seen Coming in over the sea in Sussex. Flower beds in gardens on the south coast were smothered with these fine insects.

The invasion seems to have extended over the whole of our southern shores as far as Western Ireland and during March well over a thousand P. cardui, Linn., were recorded, some from as far north as Scotland. Coupled with this amazing incursion were several other migrant species of moths. T h e Small Mottled Willow (Laphygma exigua, Hübn.), was obtained in some numbers at light over a wide area in the south. Several of the Bordered Straw (Heliothis pelligera, Schiff.), were taken, one in Piccadilly, while some ten specimens of the rare Ni moth (Plusia ni, Hübn.), were recorded in many of the southern counties and in one instance ova were obtained and a Iarge generation subsequently bred. There were also several of that great wanderer, the Striped Hawk (Celerio Ikomica, Esp.) One was caught in Lancashire in mid-March. Most remarkab'e of all was the capture of two moths belonging to quite an exotic species identified as Tathorhyncus exsiccata, Lederer (vide Ent. Record, 1952, 64, pp.

131 /2). This species which had never before been seen in the British Isles has its habitat in the Oriental regions and Eastern Mediterranean. It is of interest to note that a specimen of this