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UNITED STATES NATIONAL MUSEUM BULLETIN 224 



coarse bristles arising from microtubercles; these be- 

 come longer below and reach to the apex of the pro- 

 boscis. Pile absent. The front is short with unusually 

 numerous, long, stout bristles on either side leaving the 

 medial half nearly bare and pollinose. Vertex not at 

 all excavated or with only a very slight depression, the 

 ocellarium is low and inconspicuous with 3 to 5 pairs 

 of bristles. Anterior eye facets only slightly enlarged. 



Thorax: The thorax is nearly bare, in part faintly 

 pollinose, with greatly reduced pile which may be either 

 fine and comparatively abundant down the middle of 

 the mesonotum, or may entirely consist of stiff, pos- 

 teriorly curved scattered setae. There is an acrostical 

 double row of such pile or setae. There are no dorso- 

 central bristles differentiated from the wide anterior 

 band of setae, but there are 3 or 4 pairs of long, stout, 

 postdorsocentral bristles in front of the scutellum. The 

 lateral complement of bristles consists of 5 to 7 hu- 

 meral, 1 posthumeral, 3 or 4 notopleural, 4 supraalar, 

 2 to 3 postalar, and 1 to 3 scutellar pairs. The anterior 

 propleuron bears a collar of about 12 pairs of ex- 

 ceptionally stout bristles, the posterior propleuron 

 laterally with a cluster of 6 or more. The lateral 

 propleuron has rather dense, coarse, bristly pile. Pro- 

 sternum dissociated. The posterior half of the meso- 

 pleuron and upper middle of sternopleuron and the 

 hypopleuron bear a number of fine, bristly hairs. 

 Upper corner of the pteropleuron with a tuft of pile 

 or sometimes 2 rather stout bristles. Anterior tegula 

 with bristly hairs. Lateral and ventral metasternum 

 with a few hairs; the postmetacoxal area membranous. 



Legs: Bristles abundant, short but unusually stout. 

 Pile of legs everywhere dense, but short and appressed 

 setate. On the hind femur are 5 lateral, a pair of sub- 

 apical dorsal, and at the apex 1 dorsolateral and 3 

 medial bristles. There is also 1 long, stout, subapical 

 medial bristle and a ventromedial row of 7 bristles. On 

 the hind tibia are 4 rows of bristles, 7 dorsolaterally, 6 

 dorsomedially and also 6 ventromedially, and 4 ventro- 

 laterally. The apex bears 12 bristles, 3 of which are 

 medial, 2 lateral, and 1 dorsal. The middle femur 

 bears 4 prominent anterior bristles, 7 anteroventral, 10 

 posteroventral, and near the apex in a row 2 stout 

 posterodorsal bristles. On the anterior femur the an- 

 terior bristles are much shorter and weaker. There are 

 7 posteroventral bristles and near the apex 4 postero- 

 dorsal bristles, as well as 5 anterodorsal situated quite 

 at the apex. Both front and middle tibia with 7 to 8 

 bristles in each row except the ventral row, where there 

 may be as few as 2 and neither with anteroventral 

 bristles. Apex of anterior tibia without spine. Claws 

 only slightly pointed, stout, strongly curved at the apex, 

 the pulvilli long and broad, and the empodium blade- 

 like. 



Wings: The wings are broad, usually brown or 

 blackish, marginal cell open, the fourth posterior cell 

 closed with a short stalk or narrowly open. Anal cell 

 narrowly open or closed. 



Abdomen: The abdomen is robust, nearly as wide 

 as the mesonotum and the first segment fully as wide. 



Sides of abdomen parallel and the whole cylmdroid. 

 The pile consists of scattered, appressed setae and a 

 tuft or patch of longer, erect, bristly pile on the sides 

 of the first and second tergites. First tergite laterally 

 with 5 to 12 bristles, some of which may be almost spine- 

 like. Males with seven tergites, females with eight, 

 the last of which is prominent. Male terminalia rotate 

 180 degrees, the epandrium completely divided and 

 also separated into short forceps. The gonopod is the 

 same length as the upper element, but separated from 

 it by a narrow cleft. ITypandrium quite short, the 

 gonopod very broadly separated below, leaving the inte- 

 rior of the terminalia widely open. Female with 9 

 pairs of stout spines upon the acanthophorites. 



Distribution: Nearctic: Dizonias pilatei Johnson 

 (1903) ; tristis Walker (1851) [ = quadrhnaciilatus Bel- 

 lardi (1861), bicinctus Loew (1866), albifasciatus Back 

 (1904)]. 



Neotropical : Dizonias bromleyi Carrera and d'An- 

 dretta (1950) ; lucasi Bellardi (1861) ; p/ioenieurvs 

 Loew (1866). 



Genus Tolmerolestes Lynch Arribalzaga 



Figuees 113, 472, 913, 922, 1922, 1968 



Tolmerolestes Lynch Arribalzaga, Ann. Soc. Cient. Argentina, 

 vol. 11, p. 27, 1881. Type of genus : Tolmerolestes pluto 

 Lynch ArribAlzaga, 1SS1, by present designation. This is 

 the second of three species. 



Closely related to Dizonias Loew, from which it is 

 separated chiefly by the more prominent face with the 

 abrupt ledge shortly below the antenna. The antenna 

 is somewhat shorter. An additional distinction lies in 

 the concentration of many, very stout bristles on the 

 upper half of the occiput. In Dizonias they are rep- 

 resented by a cluster or row of some 9 elements on each 

 side; the stout bristles of the pronotum and lateral pro- 

 notum are exceptionally numerous and the acrostical 

 pile is differentiated in Tolmerolestes. From Cyli- 

 comera Lynch Arribalzaga, to which it is also related, 

 it is separated by the presence of acrostical pile, the 

 more prominent ocellar tubercle, the dorsal facial ledge, 

 the longer second antennal segment, and the bare disc 

 of the scutellum. Length 18 to 20 mm. 



Head, lateral aspect : The head is comparatively long 

 because of the prominent occiput and face. The face, 

 while nearly plane in profile, is considerably extended 

 beyond the eye except for a short distance beneath the 

 antenna, as which point it is extended forward leaving 

 an abrupt ledge. The occiput is low along the eye mar- 

 gin but a short distance from the eye it begins to in- 

 crease in thickness to a considerable extent. The pile 

 on the ventral portion is coarse, stiff and abundant, and 

 bristles begin below the middle of the head, form 2 to 3 

 rows, and become exceptionally stout and numerous 

 dorsally. Each side of the head contains at least 40 

 stout bristles. Proboscis prominent, considerably ex- 

 tended beyond the face, narrowed at the immediate 

 apex to a blunt point and a little widened from the dor- 



