Hood—Studies in Tuhuliferous Tli.ysaiiopiera. 
105 
()1 these genera one pair of cephalic, bristles, ordinarily niinnte and in¬ 
conspicuous, is reniarkahly produced and thickened. In Diclixtothrips 
this i)air is the postocellar one; while in Diceratothri])s it is a pair on the 
vertex, laterad of the median ocellus. The short, broadly rounded mouth 
cone, the stout tube, and the short, broad, semicircularly emarginate 
]trothorax with its thickened anterior margin, are also distinctive. This 
last character .seems to he uni(pie, all other genera having this margin 
very weak, sometimes grading insensibly, or even irregularly, into the 
granulate membrane connecting the thorax with the head. iMr. Bagnall, 
after a study of the single specimen from wliich the genus is described, 
('xprt'ssed himself as agreeing with the above interpretation of its allinities. 
Dichastothrips brevicollis sp. nov. 
(Plate 4, lig. 7.) 
Female .—Length about M.T mm. Surface shining. Color nearly uni¬ 
form piceous black, with tarsi and fore tibiffi yellowish. 
Head suhrectangular, J.(3B times as long as wide; vertex not produced, 
evenly declivous; frontal costa deeply and roundly emarginate; cheeks 
nearly parallel, very slightly converging to a .short, abrupt, collar-like, 
basal widening; dorsal and lateral surfaces smooth, with about three 
pairs of short lateral spines, of which one (the largest) is on a line with 
the postocular bristles, the other two in basal third; postocular bristles 
pointed, two-thirds as long as head ; {tostocellar bristles nearly as prom¬ 
inent as the postoculars, almost half as long as head. Eyes slightly less 
than one-fourth as long as head, suhrectangular in form. Ocelli moder¬ 
ately large, their diameter about three times as great as that of facets of 
eyes ; anterior ocellus apparently slightly overhanging, pointing directly 
forward; posterior ocelli widely separated, nearly contiguous to margins 
of eyes at a line drawm through middle of anterior half. Antennae about 
lM times as long as head ; segments :5-7 claviform, elongate, 3-5 inflated 
in apical third, 4 and 5 both longer than 3; 8 nearby fusiform; sense 
cones long, slender, those on segment 3 nearly five-sixths as long as the 
segment itself. Color of antennae: Nearly black, with base of segment 1, 
apex of 2, and base of 3, yellowish. 
Prothorax along median dorsal line about one-third as long as head 
and (inclusive of coxm) about 3.8 times as wide as long ; posterior margin 
and sides nearly straight; anterior margin almost semicircularly emargi¬ 
nate, conspicuously thickened; anterior marginal and anterior angular 
bristles minute, about erpial in size to those on cheeks; midlaterals about 
equal in length to postocellars, posterior marginals half as long (posterior 
angulars and coxals broken oil’ in the uni(iuerype). Pterothorax slightly 
wider than prothorax, sides slightly arcuate and convergent posteriorly. 
Wings long and broad, closely fringed ; fore wings slightly expanded 
apically and with about 35 interlocated hairs on posterior margin near 
apex; both pairs clouded with brown, more darkly at ba.se, and with a 
post-median dark brown vitta. Fore femora about three times as long 
as wide, almost equal in length to head; fore tarsi with a stout aud 
slightly curved tooth which is about as long as width of tarsus. 
