120 



EEPOET 108, U. S. DEPARTMEXT OF AGEICULTUEE. 



In the male there is a smaller U-shaped mark, 

 is, however, a small apertm^e behind the anus. 



The copulatory opening of the female 

 The anal aperture is a simple slit at 



Fig. 246. — An analgesid: a, Palpus; 

 C; epimera ; d, genital opening; e 

 anal suckers; g, lobe. 



larva transforms to the nj-mph. 



b, caroncle 

 process; /, 

 (Author's illustration.) 



the tip of the body. Each side of it in the 

 male there is a circular mark or sucking 

 disk; these are the mating or copulatory 

 suckers. The tip of the abdomen is fre- 

 quently of a different shape in the two 

 sexes. In many genera the male abdomen 

 is deeply bifid or bilobed at tip, -while the 

 female has the tip entire. In some forms it 

 is more bifid in the female. In some cases 

 the tip is provided with foliaceous plates 

 or lamellae. In a few genera there are two 

 forms of the male; in one the mandibles 

 and anterior legs are enlarged. 



The development and life history' of 

 the bird mites are replete with remark- 

 able facts — facts which have puzzled in- 

 vestigators for years, and even now not 

 thoroughly understood. The egg is com- 

 paratively large, elongate, and slightly 

 cun^ed. The newly-hatched larv^tie Ixave 

 six legs, but in some forms apparently but 

 four. It has been claimed tliat it is the 

 thJLi'd pair of legs that is added when the 

 The n^Tnph has the general form of the adult, but 



lacks the genital organs. In certain species there is a hj'popial stage developed 

 from the n^-naph. It is distinguished from the nymph by the 

 absence of mouth parts, and by ha\dng long hairs, instead of 

 a claw, at the tip of leg IV. This stage has on the venter an 

 area of sucking disks similar to that of the hypopus of the 

 Tyroglyphidse. The adult male is developed from the 

 nymph. But in the case of the female there is a passage 

 form between the n\Tnph and the true adult female. It has 

 been called the njonphal or copulating female (femndna ac- 

 coppiata), for it is in this stage that pairing occurs. The 

 male mates with the n^Tuphal female, but pairing is pro- 

 longed for several days or until the true adult is fully devel- 

 oped within this n^onphal female. Pairing is performed 

 through a small aperture beliind the anus and not by the 

 vulva, which latter is not developed in the nymphal female and only appears in the 

 adult. The o\'iduct opens by the vulva. Wlien the true female escapes from the 

 nymphal female, an egg, already of considerable size, is seen 

 mtliin her body. 



The Analgesidfc live upon birds, feeding on the feathers, 

 epidermal scales, etc. They rarely do any damage to the 

 birds, but are usually of service in keeping the skin and 

 feathers clean. They remain on the host after death, often 

 leaving the feathers and congregating on the skin. Although 

 many of the species are now known from but one host, there 

 are some common forms that occur on a considerable number 

 of birds, frequently of different genera. Likewise several 

 species of mites sometimes occur on the same bird. One species is known to occur 

 on birds belonging to five different families. However as a rule they do not spread 



Fig. 247.— Caroncle of Pfero- 

 lichus. (Author's illtis- 

 t rat ion.) 



Fig. 248.— Leg oi Analgcs: 

 0, Olecranon process ; p, 

 tarsal process. (Au- 

 thor's illustration.) 



