May-beetles by M( iarrJiizinm, as result of the behavior of the fungus 

 in its attack on FhyllopJiaga vandinei: 



(1) Judging from its behavior in jars containing niunbers of adults con- 

 fined togetlier, tlie fungus had every a^ipearance of being transmittable. 



(2) In jars containing only two adults, the fungus gave no indication of 

 being transmittable. Out of 25 such jars in which at least one beetle contra'?ted 

 the disease, in only two (or 8 per cent of them) did both beetles of a pair become 

 infected. 



(3) In the case of grubs, transmission of the fungus from one grub to 

 another was not possible, since practically all of the grubs that became infecied 

 were reared in individual boxes. Infection must have taken place through the 

 soil. 



(4) Comparing the infection of adults and of third instar grubs, it appears 

 that a higher degree of infectation may be brought about through the medium of 

 infection from the soil than through transmission of the disease by contact. 

 There is no proof that transmission by contact ever takes place. 



(5) Attempts to artificially infect grubs Ijy the introduction of dry spores 

 into rearing boxes were unsuccessful. 



(6) Since all infected specimens, when found, were at once removed from 

 rearing boxes and preserved, artificial increase of the number of spores in the 

 soil used was certainly very limited. It obviously required a very small quantity 

 of the spores to infect a large number of grubs and beetles. 



(7) Spores were at no time introduced into the soil by the writer, so must 

 have existed naturally in the soils of the district where the experiments were 

 made. This w'as proved by the finding, outside the insectary, of the following 

 insects infected with the fungus: 



Aphodius sp., two adults under manure in stock lot. 

 Canthon sp., a dozen or more adults in an outdoor cage. 

 Strategus titanus, one adult in an outdoor cage. 

 Ligyrus ttimulosm, several adults in an outdoor cage. 

 Phytahts insiilaris, several grubs in an outdoor cage. 



(The last four si'ecies were in separate cages, removed some feet apart, with 

 no intermixing of soil from one to another.) 



(8) Shipments of MetarrMzium spores were made by Mr. Van Dine, in 

 3911 and 1912, to Mr. T. C. Murphy of Guanica Centrale, who propagated the 

 fungus extensively on May -beetles in the same hacienda (Santa Rita) where the 

 writer 's experiments were conducted. Later shipments of spores to the some 

 district were also made by the pathologists of the Station, Mr. Johnson and Mr. 

 Stevenson. This may have accounted for the prevalence of the disease in the 

 insectary. 



(9) Neither in grubs nor adults was there, ordinarily, any sickness or other 

 visible abnormal condition immediately preceding death. Often grubs in perfect 

 condition would succumb to the disease in a week's time or less, making it appear 

 that death was caused by the disease alone. 



(10) In some cases infection was aggravated by ]>revious attack of fhe 

 grub by mites or bacterial disease. In case of the latter, tlie dead grub usually 

 became only in part infected by the fungus, as though the latter were a .sapro- 

 phyte, whereas in grubs perfectly healthy before infection the entire body became 

 covered with iiivfelium, and later with spores, following death. 



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