INSECT ENEMIES OF LIVE STOCK 195 



intestine, the embryos become adult. In the United 

 States the cockchafer is unknown, so there the larvae of 

 a beetle of another genus, Lachnosterna arctuata, acts as 

 intermediate host. 



Giganthorhynchus is occasionally found in man, in 

 South Russia, where cockchafers are eaten raw. 



Two DISEASES OF USEFUL INSECTS 



In the year 1851 the most important silkworm-rear- 

 ing centres in France were threatened with almost total 

 annihilation, on account of a mysterious disease of the 

 caterpillars which had made its appearance in the Depart- 

 ment of Vaucluse six years previously. In 1856, the total 

 production of silk, in France, had been reduced by seventy- 

 five per cent., and severe losses were also experienced in 

 Italy. In the latter country the disease was called 

 " gattina," and in France it was named " pebrine," from a 

 local name for pepper, because spots resembling pepper 

 grains were often found upon the infected caterpillars, 

 though later researches showed that these growths had 

 nothing to do with the disease. Balbiani discovered that 

 " pebrine " was a parasitic disease, and Pasteur it was who 

 made some startling scientific discoveries, which saved the 

 silk-raising industry from utter ruin. 



The disease is caused by minute organisms, Mixosporidia, 

 to which the name of Nosema bombycis has been given. 

 These organisms are somewhat peculiar, in that they attack 

 practically every organ of the infected insect, even to its 

 silk glands, and they vary in form, according to the organs 

 in which they have taken up their position. Young cater- 

 pillars, attacked by " pebrine," become inert, and, in many 

 cases, die in numbers before pupation ; those that survive 

 the larval stage spin small cocoons, deficient in silk, and 

 sometimes die in the pupal stage. Those that are destined 

 to survive to the adult stage mate and produce eggs 

 that are infected, so that the next generation comes into 



