U. S. NATIONAL MUSEUM BULLETIN 216 part 3 



Helcostizus, and Sphecophaga. These genera, or at least those sections 

 of the genera that are represented in the Nearctic fauna, occur pri- 

 marily in the Nearctic and Palearctic regions. Our species are mostly 

 northern in distribution, many of them reaching their southern limits 

 in the Transition or Upper Austral zones. Some of them are Holarctic, 

 or have very close relatives in Eurasia. Specific limits between the 

 species as they occur in America have usually been clear enough 

 when we have had sufficient material, but some questions of specific 

 identity with Eurasian forms remain unanswered (or even unasked) 

 for lack of specimens. Since our area is part of the center of distri- 

 bution of these genera some of the generic distinctions have to be 

 partly arbitrary, there being some species with intermediate characters. 

 The distinctions between Agrothereutes , Gambrus, Aritranis, and 

 Pycnocryptus; the distinction between Habrocryptoides and Tra~ 

 chysphyrus; and that between Hidryta and Idiolispa are cases in point. 



Faunal connections with Eurasia are through the Bering Strait 

 area. In general, the species, subspecies, or races in western and 

 northwestern North America are more like those in Eurasia 

 than are the species, subspecies, or races in the eastern and southern 

 parts of North America. Those species that are Holarctic tend to 

 range to the Northwest or to be restricted to that area. The strictly 

 eastern species appear not to occur also in Eurasia. Exceptions to 

 the above generahzations are Hemisphragia, Trachysphyrus moschator, 

 and Pycnocryptus director. The case of Hemisphragia is discussed 

 below. Pycnocryptus director is known to have been introduced to 

 America within the last fifty years, so its occurrence only in eastern 

 America is not from natural spread. The case of Trachysphyrus 

 moschator may be due to incomplete collections. 



The genera meriting special mention are as follows : Habrocryptoides 

 seems to be a reUct group, with species scattered over Eurasia and 

 North and South America. The faunal relations of our species are 

 unclear. Hemisphragia is another genus with a relict distribution. 

 We know two species from Madagascar, one from China, and one 

 from southeastern United States. A faunal connection between 

 China and southeastern United States is rather common among 

 groups inhabiting moist, temperate, deciduous forests, and the case of 

 Hemisphragia seems to be another illustration of this. Trachysphyrus 

 is a widespread genus, but our species belong to groups that are 

 entirely or largely Holarctic in distribution, except possibly for T. 

 rugosiscutum. This latter species appears to have Neotropic affinities. 



Sonoran: This group of genera includes Lanugo, Reptatrix, Comp- 

 socryptus, Joppidium, Mesostenus (Longicaudis group), and Crypto- 

 helcostizus. Of these, Cryptohelcostizus is related perhaps to the 



