THE MUD-DAUBERS. 189 



only the abdomens of the first four or five spiders that it attacks, 

 but after this it eats the cephalothorax and even the legs, of one 

 before passing to the next. Later on, it may return to the 

 harder parts that were neglected at first and devour them also, 

 finishing up, last of all, with any broken pieces of legs that may 

 have been overlooked. There are exceptions to this order, for 

 some larvae do not leave the first spider until the whole body is 

 consumed, but in all instances where the supply of food is 

 plentiful, many of the legs, and sometimes whole spiders are 

 left. Our study of the eating habits of these larvae has led us 

 to the conclusion that they are not in the least fastidious as to 

 whether the food is hard or soft, fresh or dry. Their habit of 

 eating only the abdomens of the first spiders comes about from 

 the fact that when the abdomen is consumed it is broken from 

 the cephalothorax and in squirming around in search of an- 

 other piece they are likely to come into contact with another ab- 

 domen. As they grow larger and stronger they eat the whole 

 spider at a sitting, be he alive or be he dead. Perfectly dry 

 spiders furnish as much proteid matter as the same number of 

 fresh ones. On several occasions when playing nurse-mother 

 to a number of growing larvae, which we kept in little glass 

 saucers, where we had not provided a large enough food supply 

 we made good the deficiency by adding a number of dead and 

 dry spiders that we had had on hand for some three weeks. 

 These were accepted by our infants, and were greedily devoured. 

 For from nine to fifteen days the larvae pass both days and 

 nights in eating. They consume, in that period, from five to 

 twenty spiders, the number being determined by their size. As 

 we are writing this, two larvae on our table are just entering the 

 cocoon stage. One of these has eaten six spiders, leaving a 

 few legs, while the other has devoured fourteen with the excep- 

 tion of half-a-dozen legs and the cephalothoraces of two, but in 

 the second case the spiders were young and small, while in the 

 first they were nearly full grown, so that this one is really the 

 bigger glutton of the two. Whether the spiders used are large 

 or small depends primarily upon accident. The wasp takes 

 whatever she happens to run across, provided always that it is 



