746 Journal of the Department of Agriculture. 



could not obtain even a bubble of air, but upon removal tliey soon 

 recovered. The vinegar had no effect at all, 



(b) A sample was prepared by dropping the beetles into boiling 

 water, which, of course, produced instant death. 



(c) Inserting a little cotton-wool, saturated with carbon bisul- 

 phide, into the tin containing the beetles was the most convenient 

 method, and, as will be seen later, proved to be the best one. 



Method of Drying. — When spread in thin layers upon the floor 

 of a dry room the beetles dried well enough without the use of 

 aitificial heat. 



Loss in Weight by Dryiiig. — Beetles collected in December, killed 

 with carbon bisulphide, weighed about an hour after death and again 

 on 15th January, 1919, showed the following losses in weight: — 



Lot 1 lost TO. 2 per cent, in 44 days; Lot 2 last 60.5 per cent, 

 in 43 days; Lot 3 lost 65.0 per cent, in 42 days; Lot 4 lost 

 60.6 per cent, in 41 days ; Lot 5 lost 64.4 per cent, in 40 

 days; Lot 6 lost 65.0 per cent, in 40 days. 



Number of Beetles per Quart and per Found. — About one hour 

 after being killed with carbon bisulphide the beetles (i.e. M. oculata) 

 were measured and weighed. It required from 275 to 300 to fill a 

 quart measure and from 300 to 400 to weigh a pound. 



Results of Analyses. — Two lots of Mylahris oculata were prepared, 

 one by killing the beetles with carbon bisulphide, the other by drop- 

 pinp- them into boiling water. These beetles were analysed at the 

 laboratory of Dr. C. F. Juritz, Agricultural Research Chemist, Cape- 

 town. Dr. Juritz reported (8) the results as follows: — 



Lot 1, killed by carbon bisulphide: 1.19 to 1.20 per cent, of 



cantharidin. 

 Lot 2, killed by boiling water: 0.66 to 0.69 per cent, of 

 cantharidin. 



The boiling water evidently causes a great loss of cantharidin, as 

 is seen by the difference between the two lots. Many of the beetles of 

 Lot 1 had been kept alive for twenty hours, and had lost weight by 

 excretion, but this will account for only a small part of the dilference 

 in cantharidin content, not more than one-tenth at most. If the 

 beetles are to be used they should be killed with carbon bisulphide. 



Dr. Jurit/ obtained also a supply of Mylahris luniita from 

 another source. These contained 1.15 per cent, of cantharidin. A 

 mixed lot of museum specimens of Cyaneolytta subcoriacea and 

 (,'. pectoralis yielded only 0.9 per cent. 



Commercial Possibilities. — The results of analyses show that our 

 Mylabris beetles are much higher in cantharidin than is Canthans 

 vesicatoria, and should the necessity ever arise they can be employed 

 for the production of the drug. However, the demand for cantharides 

 is at present so limited, according to the statement of a leading whole- 

 sale chemist, that it would be difficult to find a ready sale for the 

 beetles. 



Moreover, the beetles, unlike the " Spanish Ely " of Europe, are 

 not gregarious : they must be captured one, two, or three at a time 

 instead of in masses; and, as already stated, the number present is 

 nearly always greatly over-estimated. If five hundred beetles are 



