96 EXTRACTS FROM FOREIGN PERIODICALS. 



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EXTRACTS FROM THE FOREIGN PERIODICALS. 

 Zoology. 

 1. The Chigger Flea {Pidex penetrans). — M. Duges, of Montpellier, has 

 lately published an interesting account of this insect in the Annales des Set* 

 ences naturelles. In writing his former memoir on the genus Pulex, in the 

 same Journal, he knew nothing with certainty of the above species; reduced 

 to accounts which could be of little value, and deceived by a caudal appen- 

 dage which is probably nothing more than the penis of the male, he expected 

 it would form a genus by itself. Actual observations made upon specimens 

 preserved in spirits, have, however, convinced him, that this insect only differs 

 from the rest of the genus in slight particulars, and especially in its habits, 

 which would not warrant the formation of a new genus. After noting some 

 particulars relative to the Fleas which infest the clothes of the bathers on the 

 shores of the Mediterranean in such numbers, and after extracting some ob- 

 servations on P. penetrans, from M. Aug. de St. Hilaire's Voyage au Bresil, 

 we find some further remarks on the latter insect. The author ascertained, 

 that the Chigger Flea settles between the epidermis and the cuticle, by cutting 

 through the latter. It proceeds then by increasing the small hole which 

 the animal has already made in the skin, and this may be done without the 

 person on whom the insect operates feeling any pain, or losing even the 

 smallest quantity of blood. The insects generally lodge themselves under the 

 nails; M. Saltzmann has had them on the soles of the feet and the palms of 

 the hands. In the specimens preserved in spirits, M. D. did not find the 

 rings of the abdomen which pass through the hole in the epidermis, protruding 

 from the skin, and making the vermicular motion spoken of by M. de St. 

 Hilaire. Perhaps the latter only takes place at the period immediately fol- 

 lowing the incision of the insect. In the individuals examined by M. D., the 

 abdomen appeared entirely membranous; but in the region of the anus cor- 

 responding to the opening of the epidermis under which the animal was 

 lodged, an orifice, surrounded by plates, was found. This circumstance con- 



