Proceedings of 

 the United States 

 National Museum 



SMITHSONIAN INSTITUTION • WASHINGTON, D.C. 



Volume 124 1968 Number 3644 



Studies in the Tiphiidae, X * 



Hylomesa, a New Genus of Myzinine Wasp 



Parasitic on Larvae of Longicorn Beetles 



(Hymenoptera) 



By Karl V. Krombein 



Chairman, Department of Entomology 



Hylomesa differs from its closest relative, Mesa Saussure, in a num- 

 ber of characters of generic significance, the most important of which 

 reflect a change in prey preferences from soil-inhabiting scarabaeid 

 larvae to wood-boring cerambycid larvae. The porrect, quadrate head 

 and generally more slender body of the female are obvious adapta- 

 tions for traversing the narrow tunnels of wood-boring beetle larvae; 

 one is reminded of similar head and body shape in such bethylid 

 genera as Scleroderma and Nesepyris, which also parasitize wood- 

 boring beetle larvae. The stout, slightly curved mandibles of Hylomesa 

 with an inner subapical tooth are adapted for chewing through wood 



1 Previous parts of this same series are: I, Krombein, 1937, Ann. Ent. Soc. 

 America, vol. 30, pp. 26-30; II, Krombein, 1938, Trans. American Ent. Soc, 

 vol. 64, pp. 227-292; III, Krombein, 1938, Ann. Ent. Soc. America, vol. 31, 

 pp. 59-60; IV, Krombein, 1940, Trans. American Ent. Soc, vol. 65, pp. 415- 

 465; V, Krombein, 1942, Rev. Ent., vol. 13, pp. 308-353; VI, Mickel and Krom- 

 bein, 1942, American Midi. Nat., vol. 28, pp. 648-679; VII, Krombein, 1949, 

 Proc Ent. Soc Washington, vol. 51, pp. 45-73; VIII, Allen and Krombein, 

 1961, Trans. American Ent. Soc, vol. 87, pp. 57-66; IX, Allen and Krombein, 

 1964, Trans. American Ent. Soc, vol. 89, pp. 211-275. 



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