14 A REVISION OF THE TYROGLYPHID^. 



4. Of the terminal abdominal bristles at least six or more are very long, nearly 



as long as the body 5 



Of the terminal abdominal bristles only two are about as loTig as the abdo- 

 men; leg I of male greatly thickened, and with a spine at apex of femur 

 ))e]ow farinse. 



5. Bristles of body distiiictly plumose or pectinate; tarsi very long Jongior. 



Bristles of body not pectinate 6 



6. Cephalothorax very short; legs I and II of male stouter than usual Iirerirep.s. 



Cephalothorax longer, legs normal 7 



7. On living trees, usually with scale insects; third and fourth joints of liind 



legs more than twice as long as broad; abdominal bristles long coccipliilus. 



On mushrooms, or decaying matter; third and fourth joints of liind legs not 



twice as long as broad ; al)dominal bristles very long Untueri. 



In mills, stored foods, grains, etc. ; third and fourth joints of hind legs scarcely 



twice as long as broad ; abdominal l)ristles shf)rter americanus. 



Tyroglyphus farinse De Geer. (PI. II, tig. 1-t.) 



Cephalothorax with four long .subequal bristles above in a trans- 

 verse row, a short pair in front over the mandibles; one on each 

 humerus, not as long as width of body, and a very short one near by; 

 two pairs on the middle of dorsum, rather farther back than usual, 

 the posterior pair the longer, but these not more than one- half the 

 length of the abdomen; two hairs on each posterior side, not one-half 

 the length of abdomen, and near the tip are two more pairs of bristles, 

 one of which is nearly as long as the abdomen, the other pair being* 

 much shorter; a pair of short bristles near anus below (PI. II, fig. 16). 

 Legs rather short, and the front pair thickened; in the male very 

 greatly so, and the femur provided with a sharp, apical process 

 below at tip, and two small teeth on next joint. The long bristle on 

 penultimate joint is as long as the tarsus in all legs; tarsus I (PI. II, 

 tig. IT) is scarcely' twice as long as the preceding joint, tarsus IV 

 (PL II, tig. 11) more than twice as long as penultimate joint; the 

 third and fourth joints of the hind legs are about twice as long as 

 broad; none of the hairs on the legs is spine-like. 



Length, 0.15 to 0.00 mm. 



Specimens have been examined from various localities, all, however, 

 in the North, as Marblehead, Mass., Lancaster, Pa., Adrian, Mich., 

 and Minneapolis, Minn., in mills, granaries, and seeds. 



I keep this species in the genus TyrogJyjylms^ since the genus Aleu- 

 rohius is based on a secondary sexual charactf^r; in other respects it is 

 a true Tyroglyphvs. If this genus is used, then other genera should 

 be made for 7\ lieteroinorphn^ and T. (irmipes^ which is, I think, 

 unnecessary. 

 Tyroglyphus longior Gervais. 



Cephalothorax with four long, subequal bristles in a transverse row, 

 and two shorter bristles on front margin; two long humeral bristles; 

 two pairs of submedian l>ristles on dorsum, the anterior pair more 

 than one half the length of abdonten, the posterior pair as long as the 



