SEVENTEENTH ANNUAL EEPOET. 



477 



posterior half; punctations numerous, small, equal, regularly distributed ; eyes toward 

 anterior third, similar to those of the male. Dorsal surface crossed by a marginal 

 -groove, equally distant from the border, limiting in back eleven festoons; punctations 

 and v/rinkles numerous, rendering the surface shagreened; hairs fine and not very 

 numerous. Genital pore at height of coxse II to III. Stigmata whitish, broad, 

 triangular; stigmal surface finely "punctate; stigmal pore small on elongate ridge. 

 Capitulum 1.1 to 1.5 mm. long, differs from that of the male in the following details: 

 Base longer; porose areas present, small, circular, oval, distant, divergent. Digit of 

 mandibles 175 ju long. Palpi straight, second article relatively long. Legs thin, long, 

 with long hairs; spine of coxse IV scale-like, very short; tarsi long; tarsi I more than 

 four times, tarsi IV four times as long as broad. 



Fecundated and gravid female may attain 12 mm. in length by 8 mm. in breadth. 



Nymph. — Body oval, swollen, 3 mm. long by 2.2 mm. broad, deep dirty gray. 

 Shield relatively broader, reddish, without spot in alcohol specimen. 



This tick has a wide distribution in North America and extends 

 down into South America. It is more or less common on cattle and 

 has also been found on man. 



As stated on page 456 there has been considerable confusion as to the species which 

 Linnseus originally named Acarus amerlcanus. Linnaeus' s name is based upon a tick 

 reported by Kalm (1754) from Pennsylvania and New Jersey, and described as ^'■Acarus 

 ovalis planus, macula dor soli alba.^' This description clearly covers the most char- 

 acteristic feature of the Lone Star tick; at the same time we are not inclined to deny 

 that Kalm's description might also be interpreted as referring, in part at least, to 

 Dermacentor eledus. De Geer (1778) both described and figured what he supposed to 

 be Linnseus's Acarus americarms, although he changed the name to Acarus nigua. De 

 Geer's figures show beyond a question that the species he had before him was not a 

 Dermacentor, but that it possessed the long palpi of the subfamily Ixodinae, and also 

 that it possessed the prominent spot on the posterior angle of the female scutum seen 

 in Amblyomma amerlcanum. There appears, therefore^ little or no ground for doubt 

 regarding the identity of De Geer's Acarus nigua with Amblyomma amerlcanum. And 

 even if we admit that Linneeus's description m.ay be interpreted as covering both 

 Dermacentor electus and Amblyomma americcmum, it is necessary to accept De Geer 

 (1778) as the first reviser who established the species to wdiich Acarus americanus 

 should be applied. On the rule of the first reviser, therefore, Acarus americanus 

 Linnaeus (1758) should be placed in the synonymy of Amblyomma amerlcanum instead 

 of in the synonymy of Dermacentor electus. The specific name americanus was subse- 

 quently transferred from Acaims to the genera RhyncJioprion, Argas, and Dermacentor, 

 the various authors in question believing that they were dealing with Kalm's origi- 

 nal form, and overlooking the important illustration published by De Geer. It is 



Idem, 1892c, p. 237.— FraxNcis, 1894, p. 451.— Mayo, 1897, pp. 126, 127.— 



NiLES, 1898, pp. 26, 27, 30, pi. i, figs. 1-4.— Idem, 1898, pp. 46-50. 

 1896: ''Amblyomma unipuncta" (Packard) of Osboen, 1896, p. 261.— Mayo, 1897, 



pp. 126, 127.— Morgan, 1899, pp. 128, 129, 130-133, 134, 141, pis. iii-iv. 

 1896: "Ixodes amerikanus'^ of Schneidemuhl, 1896, p. 340. 

 1896: ''Amblyomma amerikanum^^ of Schneidemuhl, 1896, p. 340. 

 1899: Amblyomma unipunctatum (Packard) of Neumann, 1899, p. 211, as syn. of 



AmMyomma amerlcanum. 

 1898: "Amblyomnia unipuncta Pack." of Dalrymple, Morgan & Dodson, 1898, p. 



241 (misprint for Amblyomma unipunctatum). 

 1899: "Amblyoma unipuncta Pack." of Lewis, 1899, p. 3 (misprint for Jxmbly omnia 



unipunctatum). 



