102 BULLETIN 66, UNITED STATES NATIONAL MUSEUM. 



the apical third on the inner margin. Posterior margin of oral orifice 

 angularly emarginate. Spiracles lateral, but hardly prominent. 



A large series of this species were collected, and much of the 

 material in the biological portion of this article was obtained from 

 the study of this species and its relations to its hosts. 



Type.— Cat. No. 10088, U.S.N.M. 



Dedicated to the writer's friend, Mr. J. C. Crawford, who dis- 

 covered the host as well as the parasite. 



14. STYLOPS CRESSONI, new species. 



Host. — Andrena (Opandrena) cressoni Robertson (det. H. L. 

 Viereck) ; Waldoboro, Maine, on Viburnum, June 16. Described 

 from one female and its offspring from the collection of H. L. Viereck 

 (pi. 3, fig. 6). 



Female. — Length of cephalothorax 0.88 mm., breadth at spiracles 

 0.91 mm., breadth at base of head 0.49 mm., distance between 

 mandibles at base 0.13 mm. Cephalothorax light yellowish brown 

 with dark brown band at base equally divided by basal line of cephalo- 

 thorax; slightly broader than long, broadly trapezoidal, truncate 

 at apex; truncation one-third the breadth between the spiracles. 

 Lateral margin constricted at base of mandibles, rather wavy thence 

 to spiracles. Mandibles obtuse, armed with outwardly curved 

 tooth at inner apex, emarginate on outer apical angle. Mouth 

 elliptical. Spiracles dorsal, just barely surpassing margin. 



Triungulinid: Length of body 0.13-0.15 mm., length including 

 stylets 0.20-0.24 mm., breadth at base of head 0.03 mm., greatest 

 breadth 0.05 mm., breadth of ninth abdominal segment 0.03 mm. 



The characters are in general the same as described for Stylops 

 californica. 



Type.— Cat. No. 10089, U.S.N.M. 



Named in honor of the eminent Hymenopterist, Mr. Ezra T. 

 Cresson, to whose honor the host has already been dedicated. 



15. STYLOPS DOMINIQUEI, new species. 



Stylops, species, Dominique, 1891. 



In order to facilitate reference, the species figured by J. Dominique 

 has been named in his honor. The figures and the host species 

 with its type locality are sufficient to identify the parasite. The 

 immense number of host records with no indication of the characters 

 of the parasites makes it convenient when such characters are men- 

 tioned to have some specific name by which the parasite may be 

 known. It is the writer's practice in most cases to designate the 

 parasite by the name of the host, or by the name of the discoverer. 



Host. — Andrena jiessse, Panzer; Nantes, France, April. The figures 

 were based upon the parasites from a quadristylopized andrena. 



