THE ACARIXA OR MITES. 



79 



■ Megisthanus floridanus. (Author's 

 illustration.) 



.t almost uninhabitable for the fowls by midsummer. The same or an allied species 

 )ccurs on cage birds. 



The genus Lophoptes {L. patavinus Trouess.) is, in appearance, extremely similar 

 to Liponyssus, but it is described as having teeth on the jaws, and so connects this 

 subfamily with the true Parasitinse. The 

 ane species occurs on poultry in parts of 

 southern Europe. 



Of the true Parasitinae there are a host of 

 genera, or rather generic names, many of 

 which can be defined only by slight charac- 

 ters of one sex, and many were proposed as 

 subgenera. Their classification is still in a 

 very unsatisfactory condition, depending too 

 much on characters confined to one sex. 

 The following table gives only the more 

 prominent of these genera, but sufficient for 

 the study of our fauna: 



1. Tarsus I ^^thout caroncle or claws; 



dorsal shield usually entire 2 



Tarsus I with either caroncle or 



claws, or with both 8 



2. Leg I about twice as long as the 



body, ending in extremely long 



bristles; male genital aperture 



on front of sternal shield. .Podocinum. fig. 151.- 

 Leg I not much longer than body. 3 



3: Dorsal shield divided; male genital 



aperture in front part of sternal shield; body elongate; peritreme hardly 



reaching in front of coxae II Rhodocarus. 



Dorsal shield entire 4 



4. Venter with lateral chitinous plates, separate from the ventral plate, and 



extending to posterior margin of the body. 5 



Venter without separate lateral plates reaching to the tip of the body 6 



5. Anal aperture in the ventral plate Caelenopsis. 



Anal aperture in the post-ventral plate Euzeixon. 



6. Body nearly circular; legs short, first pair with quite long hairs at tip; hind 



legs without teeth on the femora; male mandibles with a brush of long 



hair; male aperture in the sternal plate Tribe Antennophorini. 



Body elongate, legs longer than width of body 7 



7. Anal and ventral shields united; male genital aperture on front of sternal 



shield Macrocheles. 



Anal shield separate from ventral; male aperture in the sternal shield; 



often ^\'ith teeth on hind femora of the male Megisthanus. 



8. With a peritreme scarcely more than twice as long as broad 9 



With an elongate peritreme 11 



9. Tarsus I without caroncle, only claws; leg I very long and slender; male 



aperture in sternal plate ; stigmal plate circular Epicrius. 



Tarsus I \\'itli caroncle and claws; all legs short and stout; male genital 

 aperture in front of sternal plate ; stigmal plate about twice as long as 

 broad 10 



10. Coxae with spines; leg I with stout bristles Paragreenia. 



Coxx without spines ; leg I with slender hairs Iphiopsis. 



11. Dorsum with several small and two large shields Sejus. 



Dorsum with at most two large shields 12 



12. Male genital aperture in the middle of the sternal plate; female with the 



ventro-anal plate occupying nearly all the space behind hind coxse, 

 not united to the genital plate; vulva not large; claws of hind tarsi not 



long pedicellate 13 



Male genital aperture in front of the sternal shield; in the female, when 

 anal and ventral x>lates are united, it does not occupy all the space behind 

 hind coxse 14 



8S854' 



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