1899] ENTOMOLOGICAL, NEWS. 155 



into another house "/here the family is at dinner and contaminate 

 the food set before them with the germs of the cholera carried in 

 the mouth parts and feet ot the insects. Some of the family sicken 

 and die, yet no one of them will ever, perhaps, suspect that the flies 

 may have carried the germs, as supposed above. for miles from some 

 other case. The safeguards are to at once clear away, disinfect 

 with corrosive sublimate solution or scald the spots where the 

 vomit has been tin-own, and to be vigilantin the use of fly-screens. " 

 During the civil war, Professor Joseph Leidy pointed out, with 

 beneficient results, that the common house-fly was instrumental in 

 spreading the contagion of hospital gangrene. The same speaker 

 stated that he thought it probable that there was in nature an 

 almost mathematically exact percentage of immunity from all 

 diseases in man and the lower animals. This accounts for the fact 

 that many people drink water contaminated with the bacillus of 

 typhoid fever and do not get the disease. In insects the same idea 

 holds good, as a certain amount of immunity from parasitism pre- 

 vents the destruction of the species. This immunity may vary 

 from year to year, but will probably average about the same. Dr. 

 John B. Smith said that the general law of immunity and parasit- 

 ism was of interest in economic entomology, the balance between 

 organisms being nicely adjusted, and seldom materially disturbed. 

 The larva of the moth,Te)'as oxycoccana,i never parasitized in the 

 first brood, frequently in the second brood, and almost certainly in 

 the third brood. The life history of the "Elm Leat Beetle" was 

 mentioned, and a statement made in regard to the effect of weather 

 in favoring parasitic disease on this species. Mr Johnson men- 

 tioned the effect of cold in driving away Heliconius charttoiinis 

 from the vicinity of St. Augustine, Fla. Mr. Laurent exhibited a 

 blown larva of Tolype velleda, and spoke of its wonderful resem- 

 blance io the twig on which it was found. He also reported the 

 capture of a 9 of Pttmphila mystic at Mt. Airy, Philadelphia, on 

 the 5th of June. HENRY SKINNER, Recorder. 



The regular meeting of the Newark Entomological Society was 

 held Sunday, March 12th, Vice President Ke-np presiding, and 12 

 members present. 



A series of the genus Do tana and Crocota were exhibited by the 

 most ot the members for study and identification. 



Prof. Smith exhibited a series ot Knlxi/tfic ( CrocoftH, illustrating 

 the species found in this territory. Especial attention was called 

 to the varieties of nurnntfaca and the differences exhibited, not 

 only in the marking, but to some extent in the wing form. It wa- 

 suggested that no broods of the species had ever been raised, and 

 that this would give a good chance for an original piece of work 

 that could be completed in one season. The common form- in his 

 experience are riilHrinnlario and ^/vr/Vf>/v> /.-,. which shade into each 



