Superfamily SPHECOIDEA 1645 



Species Group Marginatum 



punctivertex Richards. Okla., Tex. south to Brazil. 



Trypoxylon (Trypoxylon) punctivertex Richards, 1934. Roy. Ent. Soc. London, Trans. 82: 

 333. 9. 



Genus TRYPARGILUM Richards 



Trypoxylon subg. Tnjpargilum Richards, 1934. Roy. Ent. Soc. London, Trans. 82: 191. 

 Type-species: Trypoxylon nitidum Smith. Orig. desig. 



Sandhouse (1940) is the most reliable source for identification of North American species for 

 Richards (1934) does not include all of our species. The revisions cited below include the species 

 of both Trypargilum and Trypoxylon which are considered herein to be separate genera. 



Some aspects of the ethology are unique among wasps. This genus and some species of Pison 

 are the only wasps in which males are known to assist in some of the nesting activities. They 

 remain in the nest while the female is hunting for prey and discourage attack by at least some of 

 the parasites that afflict wasps. Activities in which the males may participate include cleaning 

 out a pre-existing boring which is to serve as a nesting site, taking prey from the female and 

 placing it in the cell, and helping the female seal inner partitions of cells with mud which she 

 brings to the nest. The larvae also exhibit unusual behavior in that the cocoon which incor- 

 porates silk, other salivary secretions and mud from the cell partition is specifically different in 

 each of the North American species which have been observed. 



North American species have been reported to store 3-36 small, usually immature spiders 

 per cell. Some species use only snare-building spiders as prey, one uses predominantly 

 snare-building spiders but does include some errant spiders, and others use predominantly er- 

 rant types but with a number of snare-builders. This suggests that there are specific differences 

 in the way that groups of species hunt for prey. 



In North America members of the Spinosum, Nitidum and Punctulatum Groups nest in 

 pre-existing cavities such as hollow stems or twigs, old insect galls or mud dauber nests, aban- 

 doned beetle borings in dead wood or structural timber and in trap-nests. Our single member of 

 the Albitarse Group is a mud dauber and builds the familiar pipe-organ nest. 



Revision: Fox, 1891. Amer. Ent. Soc, Trans. 18: 136-148, 1 pi. (N. Amer. spp.). —Fox, 1894 

 (1893). Acad Nat. Sci. Phila., Proc. 45: 472-474 (revised key to N. Amer. spp.). —Richards, 

 1934. Roy. Ent. Soc. London, Trans. 82: 173-362, 56 text figs., 5 pis. (New World spp.). 

 —Sandhouse, 1940. Amer. Midland Nat. 24: 133-176, 4 pis. (N. Amer. spp.). 



Taxonomy: Krombein, 1959. Ent. Soc. Wash., Proc. 61: 152-153 (key to red-marked Fla. taxa). 



Biology: Krombein, 1967. Trap-nesting wasps and bees, pp. 178-185, text fig. 2 (male 

 behavior, cocoon differences, prey preferences, competition for nesting sites, differing 

 emergence dates). 



Species Group Spinosum 



Members of this group prey upon both errant and snare-building spiders, but prefer the 

 former by a substantial margin. 



bicalcaratum (Richards), n. comb. South. Ariz.; Mexico. 



Trypoxylon (Trypargilum) bicalcaratum Richards, 1934. Roy. Ent. Soc. London, Trans. 82: 



235. S. 

 californicum Saussure. Tex., N. Mex., Ariz., Utah, Nev., Calif., Oreg., Wash. Ecology: Nests in 



borings in wood, stores 8-19 prey per cell. Parasite: Chrysididae sp. Prey: Agassa sp., 



Habronattus sp., Metaphidippus sp., Phidippus sp., Syne7)iosy7ia sp., Salticidae spp.; 



Ebo sp., Misumenops sp., Philodromus sp., Thomisidae spp.; Oxyopes tridens Brady, O. 



sp.; Clubionidae sp.; Dictyna sp.; Araneidae spp.; stores mostly errant spiders, only a 



few snare-builders. 

 Trypoxylon californicum Saussure, 1867. Reise d. Novara, Zool. 2, Hym., p. 78. 9. 

 Trypoxylon arizonense Fox, 1891. Amer. Ent. Soc, Trans. 18: 145. 9. N. syn. (R. E. 



Coville). 



Taxonomy: Evans, 1957. Amer. Ent. Soc, Trans. 83: 92, figs. 47-48 (larva). 



Biology: Matthews and Matthews, 1968. Psyche 75: 285-293, 2 figs, (nest, prey, cocoon). 



