XX] LYPEROSIA 369 



disease may be transmitted by the bites of Stomoxys. It should 

 be added, however, that the transmission has only been effected 

 under experimental conditions and it remains to be seen whether 

 this is the usual method of infection in nature, for cases of 

 poliomyelitis have occurred in the absence of any Stomoxys. 



REFERENCES. 



Anderson and Frost (1912). Transmission of poliomyelitis by means 



of the stable-fly (Stomoxys calcitrans). Public Health Reports, 



Washington, vol. xxvii. No. 43. 

 Brues and Sheppard (1912). The possible etiological relation of certain 



biting insects to the spread of infantile paralysis. Journ. Econ. 



Entom. vol. v. No. 4. 

 KJing, Wemstedt and Pettersson (191 2). Recherches sur le mode de 



propagation de la paralysie infantile epidemique. Zeitschr. f. 



Immunitatsforschung, vol. xii. pp. 316—323 and 657-670. 

 Khng and Levaditi (1913). litudes sur la poliomyelite. Pitbl. de 



I'lnst. Pasteur. 126 pp. Paris : Maretheux. 

 Rosenau (1913). Public Health Reports, Washington, vol. xxvii. 



CHAPTER XXI 



LYPEROSIA 



General description. The genus Lyperosia is closely related 

 to Stomoxys, from which it may be distinguished by the shape 

 of the maxillary palps, which are more or less spatulate, and 

 as long, or almost as long, as the proboscis. When the insect is 

 resting the palps ensheath the proboscis, as in the case of 

 Glossina, and as a result the combined structures appear as a 

 stout rod-like process in front of the head. The proboscis is 

 long and tapering, chitinous throughout, and the labella are 

 small. The arista is feathered only on the dorsal surface. 

 The third longitudinal vein is without bristles and the fourth 

 longitudinal is gently curved distally so as to leave the first 

 posterior cell wide open. 



All the known species of Lyperosia are small, dull, incon- 

 spicuous insects, not exceeding about 4 mm. in length. 



H. B. F. 24 



