98 M. F. Plateau on the Mmcular Force of Insects, 



of the species of greater weight. The following table contains 

 the results of these arrangements : — 



from which we see that the mean forces are still in inverse pro- 

 portion to the weights. It appears to me_, therefore^ that we 

 may assume, in a general way^ and without regard to zoological 

 affinities^ that the force of insects is more considerable in pro- 

 portion as their size and weight are less. 



I devote the concluding portion of my present paper to reply- 

 ing to some objections which have been raised by my former 

 note. I think it needless to reproduce these objections, with 

 the exception of a single one which has been made by the journal 

 the editors of which have the kindness to lend me their pages at 

 the present moment. 



In speaking of the flight of insects I remarked that it did not 

 in any case furnish me with such high results as traction and 

 pushing, probably because insects have never, like certain ani- 

 mals, to transport from place to place burdens of considerable 

 weight. The ^Annals and Magazine of Natural History^ said, 

 with regard to this passage, " M. Plateau seems here to have 

 forgotten the Sand-Wasps, many of which carry caterpillars of 

 comparatively large size to their burrows." I by no means deny 

 that the Sphegidce transport, by flight, caterpillars of consider- 

 able size, but I cannot admit that these caterpillars possess 

 comparatively great weights. In support of my assertion I here 

 give the results of experiments which I have made upon Sphecc 

 sabulosa. In the following table will be found the maximum 

 mean weight which this species can raise by the force of its 

 wings alone, and the relation of this weight to the mean weight 

 of the insect : — 



