1922] Taylor — Biology of Wasps of Genus Ancistrocerus 55 



In the species of Ancistrocerus which have come to my 

 notice, the wasps which have developed from the innermost 

 cells of a nest have been invariably females. These inner cells 

 are always of greater capacity and more bountifully provisioned 

 than the smaller, outer cells, which are destined to give forth 

 maless. In a very painstaking study Fabre (1884) found a 

 similar distribution of the sexes in the nests of certain solitary 

 wasps and bees. Later Verhoeff (1892a, 1892b) made hke ob- 

 servations and gave the name proterothesie to this phenomenon. 

 Bordage (1912) and Roubaud (1916) have found it also in 

 solitary wasps of the Malagasy and Ethiopian regions. This dis- 

 position of the males and females is supposed by authors to permit 

 the males on emerging to fly about and thus come in contact 

 with females from other nests, achieving cross-fertilization. In 

 one of the nests which I had in confinement, however, (nest no. 2) 

 one of the first two emerging males constantly sat at the entrance 

 of the nest from which it had just escaped, apparently waiting 

 for a female. The next wasp to emerge was another male; the 

 new arrival was met with palpations of the antennse similar to 

 those which precede copulation. In nature, however, this might 

 not have occured. 



In confinement copulation was witnessed. The female ap- 

 parently copulates but once, as the one observed repeatedly 

 rejected males after having been fecundated. The males, on the 

 other hand, are apparently able to fertilize more than one female, 

 since they make repeated attempts after their first mating. 



The tables given above show several instances of longevity 

 among individuals of this species, both in males and in the single 

 female, one individual of each sex living longer than three months. 

 Whether the period of life would be as long under normal con- 

 ditions of subsistence and expenditure of energy is perhaps 

 questionable, but it seems highly probable that a single female 

 lives sufficiently long to construct several nests of the type 

 described in this paper. 



6This difference in size is evidently the general rule. Aberrations have been noticed and 

 one of these is shown in figure 2, where cell No. 2 is larger than No. i. This condition seems to 

 be exceptional. 



