1020 General Notes. [December, 



the fall of 1 83 1, and but a few species of insects, and those the 

 most common were obtained for trial, and from want of time the 

 experiments were necessarily incomplete. 



Oxygen. — The insects introduced in this gas at first showed 

 slight symptoms of exhilaration and excitement, moving rapidly, 

 flying, accompanied with a restless inclination to jump; this 

 passed away and the prisoners seemed totally unaffected by the 

 excess of oxygen about them and when finally they succumbed, 

 it seemed in some cases as much due to confinement as to the 

 super-excitatory qualities of the gas they were breathing. Their 

 resistance to the hurtful effects of the oxygen varied extremely, 

 both in individuals of the same species and of different species, 

 but in all cases the gas impaired their vitality only after long ex- 

 posure to its influence. 



Flies {Musca domestka) lived in the jars, completely charged 

 with oxygen, from nine through fourteen, fifteen, twenty-three, to 



Colorado beetles (/■ tfa) were confined in 



oxygen for three days, and at the end of that time showed only 

 a slight torpidity, which entirely disappeared when they were 

 liberated, and they resumed their destructive habits apparently 

 uninjured. 



The larvae of the Colorado beetle died in the oxygen after dis- 

 playing great discomfort under its action after one and one-half 

 day's exposure. 



Meal bugs {Upis pennsytvanicHs) were introduced into the ox- 

 ygen with the Colorado beetles, and behaved in a similar manner 

 though noticeably rendered more torpid and inert. They recov- 

 ered completely upon their release. * The common yellow but- 

 terfly {Colias phdodoce) fluttered convulsively in the gas, but 

 yielded to any injurious influence exerted by the gas over it, very 

 slowly, dying in twelve hours, possibly as much from the effects of 

 its own violence and consequent exhaustion, as from the power 

 of the gas. 



ility, living 



{Phalangium dorsatum) evinced considerable ex- 

 itement m the oxygen, and lived twenty four hours. 



Hydrogen. —Flies {Musca domestic*) were instantly knocked 

 own and after a few struggles became quio^nt. with complete 

 aralysis and plication of legs, in fifteen to twenty minutes, or IS 

 )me cases in five minutes. Though this prostration closely re- 

 imbled death, and was so in many instances, yet some of the 

 ies were actually alive for a long time afterwards. After twenty- 

 >ur hours confinement one fly revived sufficiently to fly, though 

 s legs remained crumpled beneath it. 



Colorado beetles evinced a wonderful vitality in this 

 :mosphere; the relation of two experiments will illustrate this. 



