6 Trans. Acad. Sci. of St. Louis 



nary time seems to be fifteen or sixteen days. Early 

 broods take longer, late broods a shorter time, so that 

 the weather, directly or indirectly, seems to be the cause 

 of these irregularities. 



From the appearance of the first young to the hatch- 

 ing of the last egg in the same nest a difference of two, 

 three or even four days is rather the rule than the excep- 

 tion, and this tends to show that incubation may have 

 set in before the last egg was laid, and it may be the 

 effect of the high temperature in the boxes during day 

 time, while the female covers the eggs at night and in 

 the morning. Oviposition takes place in the morning. 

 The remarkably large number of addled eggs, reaching 

 as high as 20 to 25 per cent, may possibly be accounted 

 for by this spontaneous incubation and subsequent 

 cooling. 



When the young Martin is six days old its eyes begin 

 to open, and when it is twelve days old it has already 

 strength enough to crawl out of the nest and take posi- 

 tion under the door. Here all the inmates, numbering 

 often four to six, are seen, closely packed, stretching 

 their necks and greeting every approaching object with 

 mouths wide open. At this period the parents are kept 

 busy in appeasing their hunger, and large numbers of 

 dragon flies, soft grasshoppers and other substantial 

 morsels disappear in the capacious throats. Sometimes, 

 however, the insect proves to be too large for one swal- 

 low, when the parent bites it in two, but otherwise no 

 dressing of wings or legs is done. In order to facilitate 

 the work of digestion, possibly also for the sake of their 

 chemical constituents, small snail shells which they 

 gather on the sandbars are fed along with the insects, 

 and some knowing mothers descend into the chicken yard 

 to pick up egg shells for an extra dish. Pieces of broken 

 china, found in the stomachs of young Martins, were 

 probaljly fed by mistake. But the busy old ones not only 



