47 



Oa the first pair of extremities tlie olecranon process on the second joint is 

 long and stout. The spine on tbe fourth joint is small, that on the fifth large. 

 The third extremity is long and rather slender, the first joint being the broadest 

 and armed about the middle of the under side with a long fine hair. The postero- 

 lateral angle of the fourth joint is extended into a long strong bristle and another 

 though somewhat weaker one arises from about the middle of the inner side of 

 the same joint. The fifth joint is slightly longer than the fourth, bending in- 

 wards and tapering to a point which bears a sucking disk. On its inner side are 

 present two blade-like bristles, one behind the other, very much as in D. 

 gladiator, but on the short fourth extremity the blunt knobs or teeth so con- 

 spicuous in the latter species are here absent. 



The female is about as large as the male, being -39 mm. long and -17 mm. 

 broad. Its shape is somewhat oblong oval, the anterior part of the body being 

 much the same as in the male. 



It is found on the White-breasted Swallow — Tachycinota bicolor. 



PTERONYSSUS, Ch. Robin, 1877. 



Body elongated; sides straight with a marked indentation between the 

 second and third pairs of feet. A little way in front of the third extremity, a 

 long lateral hair takes its origin, with a short bristle just behind it. 



The auterior pairs of feet are without either olecranon process or spines. 

 The third pair in males is enlarged, and the abdomen is small and only slightly 

 indented at its posterior end. In the females also, as in the two genera already 

 mentioned, the abdomen is undivided, and is without appendages other than 

 hairs. 



Pteronyssus simplex, Haller, is found on the Red-headed Woodpecker — 

 Melanerpes erythrocephalus. 



PTERONYSSUS SPEGTOSUS, n. sp. 

 Fi(.;. 5, Pl. I. 



Male. — The general shape is that of a long oval with the dark brown chitinous 

 epimera standing out in strong relief on the light coloured body, those of the 

 first pair of legs meeting some distance behind the rostrum at an acute angle. 

 The body is about -54 mm. long and -22 mm. broad. The abdomen is short, 

 about -12 mm. long, which is about half as long as the side of the body between 

 the second and third pairs of legs. 



On each side, running from the notch on the side of the cephalo-thorax to 

 the insertion of the third extremity are two strong dark brown bands of chitin, 

 the outer one bearing about the middle of its length a small dagger-shaped bristle ; 

 laterally from this again a fine, rather long, hair takes its origin. 



The posterior end of the abdomen is in the shape of two small semi-circles 

 meeting in the middle line, and each bearing three bristles, the middle one on 

 each side being about half as long as the body. The copulatory arches are 

 situated close to the posterior end. 



The first extremity is situated on the anterior end of the body close lieside 

 the rostrum, and is slightly stouter than the second, which is inserted toward the 

 side from, and about -03 mm. behind, it. The third is long, with the first four 

 joints of about equal thickness : and the fifth conical, with the sucking disk 

 attached slightly outwards from its point. The fourth extremity is about half 

 aslonga.s the third and inserted immediately toward the middle line from it. 

 All are provided with very large sucking disks. 



The female is of a very regular long-oval shape slightly truncated at the 

 posterior end, and of about the same size as the njale, but with the third and 

 fourth extremities of nearly equal size and inserted about -09 mm. apart. 



