“Bully idea, that, Frank, and I hope you decide to carry it out.  Just to think what a pleasant surprise it would be for our butterfly collector, expecting that he was going in to gather in another lot of plunder, and then to hear a voice say to him:  ‘Hands up! you’re our prisoners!’ Oh! wouldn’t I like to be Johnny-on-the-spot when that happens.  Wonder if they wouldn’t let us have a part in the proceedings, after we brought the news that upset the plans of the yeggmen?”

“That will do for just now, Andy, because here comes Sally again.  Let’s be gaping at the wonderful collection that almost cost the professor his very life in all sorts of hot countries, as well as a whole pocket full of money—­if you don’t care what you say.”

And when the farmer’s daughter did enter the room a minute later, she saw the two boys standing there, a rapt look of admiration and envy on their faces, as they stared at the little case of common local butterflies which possibly some boy had gathered together, and then disposed of for a song.

While the young aviators had in this fashion about decided on their plan of action, they saw no reason for any hurry.  The day was still long, and when they felt like starting toward home it would take them but a very short time to get there.

Meanwhile, there seemed to be some sort of fascination holding them to the neighborhood of the Hoskins’ farm.  And when they went away a little later it would be with the idea of hanging about, and seeing if the odd little professor might not come along.  Both of them thought they would like to look at him.  The man who was capable of playing such a clever game as this must surely be worth seeing.

Then again, the fact that Casper Blue once upon a time had been a daring birdman had something to do with this interest on the part of Frank and his cousin, because there is always a certain fellow feeling between those who are engaged in the same dangerous pursuits.  But possibly Andy on his part was hoping secretly that by spying around they might be able in some way to learn where the yeggmen had hidden the plunder they had taken from the looted Bloomsbury bank.

CHAPTER XV

WHEN CASPER CAME BACK

Although the Bird boys had more than once before proved that they possessed all the courage and daring a successful aviator must have in order to accomplish the difficult tasks hourly presented to him for solution, it must not be thought that they were reckless to any degree.

Andy might be slightly inclined that way, but Frank was an exceedingly careful navigator of the air, and by degrees his influence was even affecting his younger cousin, as example always will.