Natural History and Transformations. 83 



l)ut I have watched spretus from the egg to the imago, 

 and thousands of mounted and alcoholic specimens of all 

 ages show the stages enumerated. The transition from 

 the second to the third, however, is often imperceptible, 

 and it is not at all improbable that, as is the case with 

 many other insects, the number of molts will vary accord- 

 ing to the amount of nutrition and rapidity of develop- 

 ment. The joints of the antenna? increase with each molt, 

 from 13 in the newly hatched to 24 or 25 in the full-fledged 

 insect. 



FLIGHT AT NIGHT. 



It is the very general experience throughout the coun- 

 try subject to invasion, that the winged insects rise, as 

 soon as the sun begins to dissipate the dew, and that they 

 come down ag'ain toward evening, as the sun's rays lose 

 their power. It is a question, therefore, whether they ever 

 continue flying during the night, and one which future 

 investigation will doubtless settle. I am of the opinion 

 that during the warmer mid-summer and early fall season, 

 when the insects are departing from their northwest hatch- 

 ing grounds, they must not infrequently continue flight 

 from necessity ; for the descent of a swarm borne along 

 in a strong current of air, at an altitude of over a mile 

 above the earth, will depend more on some change in 

 strength or direction of the current than on any other 

 condition of the atmosphere. 



