89 



ditt'erent conditions. It is important therefore, that the conditions 

 under which the experiments are carried out should be varied before 

 any definite conckision can be reached. 



From 200 Phlebotomus papatasii examined, flagellates, apparently 

 Herjjetomonas, were found in four cases in the digestive tract, though 

 in only one case was the infection strong. The forms of the parasite 

 are described. Peritoneal inoculation into a mouse produced an 

 infection which caused death. 



In the digestive tract of an oriental cockroach, Blatta {Periflaneta) 

 orientalis, a new flagellate was found, which is designated Herpeto- 

 monas periplanetae. This parasite, the characteristics of which are 

 described, was found in only one individual out of 20 examined. When 

 inoculated into the peritoneum of mice, it proved pathogenic, and 

 inoculations from the hver or spleen of the infected animal into others 

 produced the characteristic ii'ifection ; while young mice are fairly 

 resistant to the parasite, older ones readily succumb. 



Sexevet (G.). Contribution a I'Etude des Ixodes. Adaptation biolo- 

 gique des Ambulacres de la premiere Paire de Pattes. — Bull. 

 ^Soc. Path. E.rol., Paris, xin, no. 2, 11th February 1920, pp. MT- 

 155, 2 figs. 



The author has made a study of the pad found at the extremity of 

 the feet of certain ticks. The presence of this pad is one of the charac- 

 ters separating the family Ixodidae from the Aegasidae ; the 

 former exhibit in every stage of their evolution pads on different pairs 

 of feet, while the latter if they possess the pads in the larval state, lose 

 them in the nymphal or adult state. It is known that the larvae of 

 Boophilus annulatus var. calcaratns, Neum., crawl shortly after 

 hatching to the top of a blade of grass, to which they attach 

 themselves by the posterior pair, of legs, leaving the first pair free. 

 If a possible host- animal passes, the ticks become violently^ agitated, 

 seeking to attach themselves to it. This would explain the develop- 

 ment of these organs for fixation. A large number of ticks were examined 

 and the pads measured, thus arriving at an average measurement 

 for various species in various stages. The results of these examina- 

 tions are given in a table, and include measurements of Ixodes ricinus, 

 L., /. hexagonus, Pack., Rhijncephalus sanguineus, Latr., Dermacentor 

 reticulatus, F., Amblyonmia cajennense, F., ^. variegatum, F., Boophilus 

 annulatus calcaratus, Neum., B. annulatus microplus, Neum., Ixodes 

 canisuga, Johns, Argas reflexus, ¥., Ornithodorus talaje, Guer., Rhipi- 

 cephalus bursa, C. & F., and Hyalomma aegyptium, L. 



It is found that the development of the pads on the first pair of 

 legs is the rule in the larval stage ; among species belonging to the 

 same genus (Ixodes) some follow the rule and some are exceptional. 

 This differentiation of the first pair of legs decreases towards the adult 

 stage, while remaining marked in certain groups. The hypothesis of 

 the adaptation of the pads to the biology of the tick seems to be clearly 

 proved, at least for the species studied. It is pointed out also that 

 the presence of this pad forms an anatomical character of great 

 importance in the classification of larvae, and also provides a method 

 of recognising approximately the mode of fife of a tick that has hitherto 



