650 PROCEEDINGS OF THE NATIONAL MUSEUM. voi,. 56. 



Tip of penis obliquely truncate and produced ventrally into a very inconspicuous 

 spur; basilar lobe merely an obtuse prominence; collar trachea pipe-shaped, with 

 slender almost straight ventral arm and very sliort swollen dorsal arm. 



T. sexmaculatus Riley. 

 Tip of penis narrowly rounded without l>arb, basilar lobe absent. 



T. weldoni Ewing. 

 Tip of penis sharply acuminate 8 



8. Penis shaft somewhat undulate; collar trachea sickle-shaped; empodial claw not 



cleft as deeply as usual, divisions closely appressed . ..T. willamettei McGregor. 



Penis shaft straight, sting-like; empodial claw divisions deeply cleft, two ventral 



divisions much heavier 9 



9. Collar trachea pipe-shaped with anterior arm about four times as long as posterior 



arm, which forms a thickened elliptical chamber T. oregonensis McGregor. 



Collar trachea L-shaped,with anterior arm about twice as long as posterior arm, 



which is of somewhat thinner caliber than the anterior arm 



T. montico lus McGregor. 



TETRANYCHUS TELARIUS (Linnaeus). 



Plate 79, fig. 7. 



1761. Acarus telarius Linnaeus, Faun. Suec, p. 4?.l. — 1804, Trombidium t. Her- 

 mann. — 1834, Tetranychus t. Duges. 



1804. Trombidium tiliarium Hermann. — 1834, Tetranychus t. Duges. — 1867, Acarus 

 t. TuRPiN. — 1875, Tetranychus t. Koch. 



1804. Trombidium mams Hermann. — 1834, Tetranychus in. Duges. 



1804. Trombidium tenuipes Hermann. — 1834, Tetranychus t. Duges. 



1804. Trombidium socium Hermann. — 1867, Acarus s. Mtjller. — 1875, Tetranychus 

 socius Koch. 



1832. Tetranychus lintearius Dufour. — 1807, Acarus I. Boisduval. — 1877, Tetranychus 

 I. Murray. 



1867. Acarus russulus \ioisv>vy PsAj. — 1875, Tetranychus r . Koch. 



1867. J.cam.5 fim Boisduval. — 1877, Tetranychus t.'^'[.v■R^RK\'. 



1867. Acarus cucumeris Boisduval. — 1877, Tetranychus c. Murray. 



1867. Acarus rosarum Boisduval. — 1877, Tetranychus r. Murray. 



1867. Acarus cinnaharinus Boisduval. — 1877, Tetranychus telarius var. c. Murray. 



1867. Acurus haematodes Boisduval. — 1877, Tetranychus telarius var. h. Murray. 



1867. Acarus vitis BoisDVV Ah. — 1877, Tetranychus v. Murukv. 



1867. Tetranychus ferrugineus Boisduval. 



1875. Tetranychus urticae Koch. 



1875. Tetranychus fervidus Koch. 



1875. Tetranychus populi Koch. 



1875. Tetranychus piger Donnadieu. 



1875. Tetranychus minor Donnadieu. 



1875. Tetranychus longitarsis Donnadiei'. 



1875. Tetranychus plumistoma Donnadieu. 



1875. Tetranychus rubescens Donnadieu. 



1875. Phytocoptes epidermi Donnadieu. 



1875. Phytocoptes gallarum Donnadieu. 



1875. Phytocoptes nervorum Donnadieu. 



Tills acarid is the pioneer of all red spiders, having first been described 

 in 1761 by Linnaeus (1), from material on linden trees, calling it 

 Acarus telarius. Throughout Europe it is best known as the linden 

 mite from which host the specific name is derived. This red spider 



