176 THE SOLITARY WASPS. 



CHAPTEK XIY. 



THE MUD-DAUBERS. 



Pelopaeus. 

 PL II., fig. 5; PL X., figs. 1-3. 



This genus is widely distributed, being found in all regions 

 of the earth, and contains a large number of species. Of these, 

 two are common in this locality, Pelopaeus cement arius, or 

 Yellow Mud-dauber, and Pelopaeus coeruleus 7 or Blue Mud- 

 dauber. The latter is much the more common of the two, and 

 its irridescent steel-blue color makes it one of the most beauti- 

 ful of our wasps. For a number of years we have given a great 

 deal of time to the habits of this genus and we are far from 

 agreeing with that mcst distinguished observer, Fabre, in the 

 opinion that its role is one of mediocre interest. The large 

 measure of individuality that we have found in the habits of 

 the different individuals that we have studied, may, it is true, 

 be only the natural result of the large number of our observa- 

 tions. Perhaps all of the solitary wasps would be found to vary 

 as widely as the mud-daubers if several hundred examples of 

 each species were carefully studied. Be that as it may, it is 

 certainly true that our mud-daubers possess all the charm of 

 marked individuality, with few defects of temper, and that they 

 lead most industrious and interesting lives. 



We have not been able to determine how many generations 

 there are in a year, but there are certainly two, and perhaps 

 three. In May or June the female makes her appearance and 

 begins the work of establishing a home. Almost invariably 

 she decides to build for herself, although now and then she uses 

 an old nest. This habit of occasionally renting an old house 

 is common to a large number of wasps that under ordinary cir- 



