TiENIOID CESTODES OF NORTH AMERICAN BIRDS. 



15 



are the only other species of this genus besides Davainea rhyncliota^ 

 in which the eggs are not grouped in Q,gg capsules. Davainea cru- 

 ciata^ as- described by Fuhrmann (1909, p. Ill) from the type-speci- 

 mens, possesses onlj^ about 200 hooks on 

 the rostellum, and the cirrus pouch meas- 

 ures only about TO/u, in length. This 

 species is therefore clearly different from 

 D. rhynchota. That D. longispina as 

 described by Fuhrmann (1909, p. 112) 

 is a different species from D. rhynchota 

 is evident from the facts that the ros- 

 tellum measures but 64iu, in diameter 

 and that the genital pore is located 

 in the posterior half of the segment. 



DAVAINEA COMITATA, new species. 

 Figures 5-8. 



This form occurs in Colaptes auratus 

 and Melanerpes erythrocephalus^ com- 

 monly in company with the preceding 

 species. It has been collected in Iowa, 

 Nebraska, and Maryland. The type- 

 specimen (from the collection of H. B. 

 Ward, deposited in the U. S. National 

 Museum Helminthological Collection, 

 No. 7234) was collected in Iowa from 



Colaptes auratus. 



External anatomy. 



Davainea comitata 

 measures 45 to 55 

 mm, in length, with 

 a maximum breadth 

 of 1.16 mm. 



The head (fig. 5) 

 is 250 to 320^ long 

 and 250 to 290/^ broad, 

 covered thickly with 



minute spines in its anterior portion over a zone 

 about 75fjL in width bordering the rostellum. This 

 spine-covered zone corresponds to the prominent 

 protuberance of the head in Davainea rhynchota. 

 The rostellum is about 90|a in diameter, armed with a crown of 

 about 80 hooks (fig. 66) 11 to 13/^ long arranged in a single row. 



m^::-^:'- ^'■'^•'' ■■■ '^ 



xqm,. 



IOQal. 



Fig. 5. — Davainea com i t a t a : 

 Head and anterior portion of 

 strobila. 



Fig. 6. — Davainea 

 COMITATA : Hooks. 

 (a) Froji sucker. 

 (6) From rostel- 

 lum. 



