Rev. A. Matthews on Species of Trichopterygide. 141 
Mean Mean Mean _ | Individual 
weights of} weights | ).j:,, | maximum 
species. moved, eee ratios. 
ae | Pees Se ee | 
TRACTION. 
Melolontha vulgaris ....| 0°940 gr. | 15-456 er. 14:3 232 
Anomala Frischii ...... Oba: 452 |ov2l 24:3 66-4 
PUSHING. 
Oryctes nasicornis ...... 2-117 gr. | 6°702 er. 3-2 4-2 
Geotrupes stercorarius ..| 0°492 ,, 8-298 ,, 16-9 28°4 
Onthophagus nuchicornis 0:056 ,, | 4457 ,, 796 92:9 
FLIGHT. 
Bombus terrestris ...... 0:214 er, | 0:154 gr. 0:63 0.87 
| Apis INGUIAER isle cinie vss 0:083: ,5|..0:066.<;, 0-78 | 1:00 
The comparative examination of the locomotive limbs in most 
of the species experimented on has shown me that the volume 
of the muscles of these organs appears in general to decrease 
more rapidly in proportion than the weight; it seems, there- 
fore, that we must attribute the greater strength of the small 
species to a greater muscular activity or energy. The reason 
of this difference in favour of insects of small size is, perhaps, 
beside all anatomical or physiological considerations: thus the 
hardness of the ground in the case of burrowing insects, the 
objects which impede their progress in simple locomotion, and 
the inertia of the air in flight, form resistances to be overcome 
which are the same for the large and small species; now to 
avoid giving a useless excess of force to the former, or fatally 
depriving the latter, nature must endow the smaller species with 
a greater muscular energy. Considerations of the same kind 
may, in my opinion, be applied to the first of the principal 
facts deduced from my investigations, namely the enormous 
strength of insects in comparison with vertebrate animals ; for if 
the reasoning appears just when applied to two insects of dif- 
ferent sizes and weights, it must be admitted, I think, with 
still more reason, when an insect is compared with a mammal. 
XVII.— Descriptions of several Species of Trichopterygidee found 
by Dr. H. Schaum in various parts of North America and 
Brazil. By the Rev. A. Matruews. 
[Plate V.] 
Tue insects described in the following pages were collected in 
various parts of North America and in Brazil by Dr. Schaum, of 
Berlin, to whose kindness I am indebted both for the privilege 
of thus introducing them to the notice of entomologists, and 
