HISTIOSTOMA AMERICANUM N. SP. 11 



median pairs on the dorsum; all of these hairs are very short, curved, 

 and often invisible. Legs rather large and long; the tarsi ver}^ slen- 

 der, tarsus I (PI. I, tig. 12) nearly three times as long as penultimate 

 joint, above with two short spines near base, and l)efore middle one 

 more, below with two rather beyond middle, and with several at tip, 

 and a long curved hair about three-fourths the length of tarsus; hind 

 tarsus fully three times as long as penultimate joint, with a short spine 

 above near base, a pair below beyond middle, and several near and at 

 tip, but no long hair. Hairs on tip of palpi much shorter than in other 

 species. 



Length, 0.30 to 0.35 mm. 



Numerous specimens on decayed leaves, Washington, D. C, August. 



Histiostoma brevipes n. sp. 



Body about one and one-fourth times as long as broad, subpyriform 

 in shape, broadl}^ rounded* behind, without very distinct humps, but 

 the posterior margin undulate; ]>chind with four simple bristles, each 

 about as long as tarsus, and a pair of similar In'istles on the posterior 

 sides; a similar humeral bristle each side. Legs rather short, first 

 pair heavy, provided with short spines; tarsus I (PI. I, fig. 11) about 

 two and one-half times as long as ])road, with two spines below near 

 middle, one above before middle, and near it is the sense hair (instead 

 of at the base); at tip above is a spine, and near by is a tine apical 

 hair, two-thirds the length of the joint; tarsus IV (PI. I, tig. 10) is 

 fully three times as long as the penultimate joint, with a spine above 

 near base, and one below near middle, and a few at tip. The palpus 

 (PI. I, tig. 8) has the usual two ])ristles, the apical one very long, longer 

 than tarsus I. and much longer than in allied species. 



Length, 0.28 to 0.33 mm. 



Several specimens from dead and diseased larvae of CyUeyie rohin!» 

 Forst. in locust at Arlington, Va., July (Hopkins). 



Very distinct by short tarsi, position of sense hair, and long hair to 

 palpus. In appearance it is nuich like Michael's 11. 2)i/rifornu\ but 

 without the long apical hairs to posterior tarsi. 



Histiostoma americanum n. sp. 



Cephalothorax divided into two parts, a broad posterior part and 

 a narrow, elongate anterior portion, in some specimens almost broader 

 in front than behind, and on its anterior margin are two long bristles; 

 below are situated the mouth parts (PL I, lig. 7). A])domen about 

 twice as long as broad, rather broader in front than behind, rather 

 rectangular in shape, almost straight across at base, weakly emargi- 

 nate behind; above with three large rounded humps each side, two 

 behind lower down on posterior surface, a median one at base 

 above, and less prominent ones on the lower sides; each of the larger 

 humps bears a short, stiff bristle. Legs quite short, with but few. 



