258 ENTOMOLOGICAL NEWS. [November, 



the hope that the facts here recorded may not only add some- 

 thing to our knowledge of insect strength, but also suggest 

 work in similar lines with other insects. 



Although the horn first suggested the idea of harnessing this 

 beetle, it was soon found that this appendage did not lend itself 

 to the purpose of these experiments as readily as had been an- 

 ticipated, so no use was made of it in the trials recorded. 

 These trials may be divided into seven principal groups as 

 follows : 



1. Power exerted by the beetles while crawling along a horizontal cork 

 surface, measured by the extension of a spring to which the beetle was 

 attached (Fig. 2). 



2. The same experiment repeated, except that a chip of wood taken 

 from one of the burrows was used in place of the cork. 



3. The beetle was allowed to crawl into an artificial burrow formed by 

 fastening a sheet of cork above a piece of wood taken from a burrow at 

 the average vertical height of the burrows (Fig. 3). This gave the most 

 natural conditions for the pull, 



4. Power exerted when climbing a vertical surface of rough wood. 

 This was measured in two ways which gave no apparent difference in re- 

 sults ; a. By the extension of a spring, the thread attached to the beetle 

 turning 90° around a pulley (Fig. 4) ; b. By loading the weights upon a 

 platform suspended directly from the beetle. 



5. Power exerted in lifting a weight by straightening the legs so as to 

 clear the ventral surface of the body from the surface on which it rested. 



6. Power exerted in lifting a weight by the head and pro-thoracic 

 muscles, the hinder part of the body being firmly fastened in such a posi- 

 tion that the insect could touch nothing with its legs (Fig. 5). 



7. A repetition of the sixth experiment with the addition of an oppor- 

 tunity for the insect to brace its forelegs so as to assist in the lift. 



In all cases the strength exerted in moving or lifting a load 

 was measured in terms of weight, determined by different devi- 

 ces as explained under each experiment. Two methods of de- 

 terming these weights were used : first, by measuring the ex- 

 tension of a spring and then finding the weight in grams which 

 would produce the same extension ; second, by adding weights 

 to a small, light platform suspended directly from the beetle. 

 In this article the weight in grams equivalent to the strength 

 actually exerted is given first, followed by figures in parenthe- 

 sis showing the ratio of the weight actually moved or lifted to 

 the weight of the insect. 



