KE VISION OF STEEPSIPTERA PIERCE. 87 



continuation of the radius; the fourth primary (medius) arises 

 contiguous to the second but rapidly diverges; between the bases of 

 these two veins is a short darkened area, about the middle this vein 

 sends off above a short slightly diverging branch indicated by an 

 infuscation, beyond this and between the main vein and its branch 

 is another infuscated branch which extends parallel and very close 

 to the main vein to the outer margin of the wing; above all of these 

 branches is an unattached infuscated vein beginning above the origin 

 of the second branch and but a little distance from the main vein and 

 extending to the outer margin of the wing; the fifth primary (cubitus) 

 diverges from the medius at the same angle as the radius does from 

 the medius; the sixth primary (first anal) is halfway between the 

 cubitus and second anal and very strong; the seventh primary (second 

 anal) diverges from the cubitus at the same angle as exists between 

 the medius and cubitus, and extends to the margin. Anterior and 

 median coxae transverse; trochanters arising at the sides, as long as 

 the femora, or tibiae ; posterior coxae prominent, cylindrical, cupped; 

 trochanters flared at apex, not as long as femora; tarsi five-jointed, 

 first joint two-thirds as long as tibia, second almost half as long as 

 first, third slightly shorter, fourth bilobed, fifth slender almost as 

 long as the third, and armed with two long slender claws. (Edeagus 

 long and slender, gently sinuate, acute at tip but not abruptly 

 angulate near tip. 



Type.— Oat. No. 10080, U.S.N.M. 



Superfamily XENOIDEA Pierce, 1908. 



Hymenopterobix (part) Saunders, 1872. 

 Stylopinx Perkins, 1905. 



Type-family. — Xenidae Semenov. 

 Tarsi four-jointed. 



The superfamily includes four families, all parasites of Hymen- 

 optera. 



2. Myrmecolacidae Pierce, parasitic on Formicoidea. 



3. Stylopidae Kirby, parasitic on Apoidea. 



4. Hylechthridae Pierce, parasitic on Apoidea. 



5. Xenidae Semenov, parasitic on Apoidea, Vespoidea, Sphecoidea. 



2. Family MYRMECOLACID^ Pierce, 1908. 



Hymenoptcrobix (part) Saunders, 1872. 

 Myrmecolacides Saunders, 1872. 



Type-genus. — Myrmecolax Westwood (1858). 



Antennae seven-jointed, third joint laterally produced, fourth 

 short, others elongate; tarsi four-jointed. 



The family includes Myrmecolax Westwood, parasitic on an un- 

 known ant from Asia, and Caenocholax Pierce with unknown host 

 from Mexico. 



