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Experiments have been made upon the vitality and longevity 

 of insects by several persons. Mr. H. C. McCook, in his 

 observations upon ants, found CamponotMS pennsylv aniens 

 capable of enduring- exposure to extreme cold without perma- 

 nent injury. A formicary was broken open in midwinter and 

 left three weeks in the open air, in the mountains ; when 

 carried to a warm house, the ants resumed their activity. He 

 also proves their power to endure extreme heat by relating an 

 instance in which ants were not destroyed nor driven away 

 from their nest by frequently making a fire upon the stone 

 beneath which they dwelt ; his own experiments in burymg 

 ants for twelve hours in mud and water to the depth of twelve 

 centimetres demonstrate their immunity from dangers of 

 flood. Messrs. S. S. Rathvon and N. Coleman each relate in- 

 stances, similar to many already known, of supposed longevity 

 in the larvae of longicorn beetles. Dr. A. S. Packard, Jr. 

 records a number of experiments on the vitality of decapitated or 

 otherwise mutilated insects, mostly Hymenoptera and Coleo- 

 ptera ; several of them, especially an Agrotis, a Hylobius and a 

 Leptinotarsa living several days after beheading. Mr. G, Dim- 

 mock has given a series of well-recorded experiments upon the 

 effects of certain gases on Arthropods, particularly on Coleo- 

 ptera. It appears that carbonic dioxide, whether alone or 

 mixed with air, is poisonous to them ; hydrogen is not poisonous, 

 and oxygen generally seems to be a stimulant. Nitric oxide 

 acts as a quick poison, from which they do not recover. 



In some notes on the circulation of insects, I have attempted 

 to show that the fluids of the body are forced, by the move- 

 ments of the dorsal vessels, into the peritracheal cavities, 

 whence, after becoming aerated, they pass into the tissues of 

 the body to perform their functions ; are thence received into 

 the general cavity, and, mingling with the fluids newly ex- 

 pressed from the alimentary canal, join the general currents 

 which flow toward different parts of the dorsal vessel, to enter 

 again the initial points of the circulation. 



We have one or two papers on the functional use of various 

 organs. Mr. L. Trouvelot has made experiments on the use 

 of the antennae. Several insects were deprived of antennae ; 



