406 Trans. Acad. Sci. of St. Louis 
CHAPTER VI. 
Tue ParriarcHate Wasps oF THE GENUS TRYPOXYLON. 
Trypoxylon clavatum Sm. [S.'A. Rohwer]. 
Other wasps are matriarchate, but in several species of 
this genus we first find them patriarchate. Of the large 
number of species of wasps described, none outside the 
genus Trypoxylon are known to exhibit paternal solici- 
tude. TZ. clavatum certainly displays this unique char- 
acteristic. The Peckhams’ have described how the nests 
of T. rubrocinctum and T. albopilosum are protected 
by the males, and elsewhere we describe this behavior 
for T. albopilosum and note for this species that mating 
often occurs when the female enters the burrow. This 
same behavior of the male has been described by Han- 
cock’ and Rau’ for 7. albitarsis (= politum). Hartman’ 
finds that the males of 7. texense remain faithfully on 
guard in the nest during the absence of the female, al- 
though he also finds a large proportion of nests without 
males. 
During the period of study, 7. clavatum gained a 
fairly good foothold in the clay bank, which was already 
beset with parasites belonging to a dozen species. Many 
of the empty burrows of the mining bees afforded very 
comfortable nests for the young of T. clavatwm. I was 
somewhat surprised to find them in this habitat, since 
previously I have recorded them as clearing out and 
utilizing old beetle burrows in wood, old nests of the 
mud-daubing wasps (Sceliphron caementarium and Try- 
poxylon albitarsis=politum), and on one occasion they 
1 Wasps, Social and Solita . 190-194. Also Bull. Wis. Geol. & 
Nat. History Surv. Ser. I, 2 7787 
2 Nature Studies in Tempera te America, pp. 210-212, 1911. 
3 Journ. Animal Behav. 6: 27-63. 1916 
4 Bull. Univ. Tex. 65: 57-60. 1905 
