284 



covered with thick yellowish- white, leathery scales, the largest meas- 

 uriug- over one incli iu diameter, and over one-tenth inch in thickness. 

 He was literally covered with scales like a fish. Upon cross-sectioning 

 one of the scales itch-mites were fonnd in abundance, and with proper 

 treatment the mites were exterminated and the skin regained its nor- 

 mal character. An interesting calculation of the number of mites 

 present on the host was made by Dr. Hessler. The estimate resulted 

 as follows: Egg-cases and eggs 7,004,000; mites, 2,009,000. It seemed 

 probable, however, that from one-half to three-fourths of the eggs had 

 already hatched, while a comparatively small prox)ortiou of the mites 

 were living at the time when the scales became detached. We are in- 

 debted to Dr. Hessler for some very fine microscopic mounts of cross- 

 sections of the scales differentially stained with picro-carmine, which, 

 resulted iu the epithelium taking the red color, the mites the yellow 

 color, while the eggs remained unstained. 



ON HARVEST SPIDERS. 



Under the title "The Striped Harvest Spider" Dr. C. M. Weed gives 

 an interesting study of specific variation in the December number of 

 the American Naturalist^ showing that Phalanginm vittatnm Say, and 

 P. dorsatum Say, are inseparable upon structural details. After the 

 study of nearly a thousand specimens Dr. Weed concludes that we 

 have to deal here with a single very variable species in which natural 

 selection has increased the size of the body and length of the legs in 

 the south and shortened them in the north. The eggs of this species 

 probably hibernate and the young of the northern form hatch in May 

 and become mature the latter part of June or July. The young pre- 

 fer the shelter of the grass, low heritage, and rubbish piles, and in Illi- 

 nois are common upon corn, where, as Dr. Weed has surmised, they 

 probablj^ live upon the numerous smaH'iusects drowned in the moisture 

 contained in the bases of the unfolding leaves as well as upon plant- 

 lice. The article is illustrated by one page plate. 



A CURIOUS PARASITE OF THE PELICAN. 



Our correspondent, Mr. Alvah A. Eaton, of Eiverdale, Calif., recently 

 sent us specimens of lice which he had taken from the gular sac of the 

 White Pelican, the accompanying note reading, "Bird killed this morn- 

 ing at 6 :30. Laid in water with head under till 12 :30. Lice alive and 

 lively at the end of that time." The specimens were determined for us 

 by Prof. Osborn as Menopon consangnineum Piaget. He writes us con- 

 cerning the species as follows : 



I have seen it a number of times collected at difterent localities, and have taken 

 niiiiihers of them from two pelicans brought here about two years ago. I formerly 

 referred the specimens to M. titan, with which it is very closely related, but Piaget 

 has seen fit to erect for it a new species and the characters are probably of suflScieut 

 importance to justify his action. 



