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ENTOMOLOGY FOR MEDICAL OFFICERS 



less and have rudimentary elytra; others {CantharincB) are 

 winged and are commonly found on flowers. Cantharis 

 vesicatoria is the blister-beetle of the B.P., but many other 

 species of the family have vesicant properties. 



(b) TenebrionidcB. A large family of dull-coloured beetles, 

 several of which are known all the world over as extremely 

 destructive to stored grain and meal. The commonest 

 species is Tenebrio molitor, whose larva is the well-known 

 meal-worm. Both larva and adult work havoc among the 

 stores of millers, corn-chandlers, and bakers. The larva 

 looks very much like a wire-worm, having the same long, 

 stiff, cylindrical body, and the same yellowish-brown colour ; 



FiQ. 106, — Tniolinm ferrugineum, from damaged grain. 



it is composed of a head with the usual appendages, and 

 of 12 body-segments, each of the first 3 of which has a 

 pair of very short legs ; when full grown it is more than 

 an inch long. The adult, which is a little more than half 

 an inch long, is shaped very much like Tribolium (Fig. 106), 

 but is almost black in colour. Another species which has 

 been spread widely in cargoes of grain is Tribolium ferru- 

 gineum (Fig. 106), the adult of which is reddish-brown in 

 colour, and less than a quarter of an inch long. Gnathocerus 

 cornutus, another grain-pest, is much like Tribolium, but the 

 male has enormous curved mandibles, which project like 

 horns. 



Of the Phytophaga also two families require notice : — 



