1921] NATURAL SCIENCES OF PHILADELPHIA. 211 



erately irregular, the former radiating. Wings with costal veins 

 almost obliterated beyond the elongate mediastine vein. Abdomen 

 with first to sixth tergites lamellate produced laterad, the first with 

 latero-caudal angles broadly rounded, the second to sixth with 

 these angles produced caudad and sharply rounded, seventh tergite 

 much narrower, eighth with very narrow caudal portion only ex- 

 posed. Supra-anal plate sub-bilobate. Cerci small and moderately 

 slender, with (9 or 10) joints strongly differentiated. Subgenital 

 plate of male of the usual asymmetrical lobiform type, with two 

 simple styles; of female ample, moderately emarginate at cereal 

 bases, truncate distad. Limbs completely unarmed, ^^ lacking 

 genicular or other spines, ventro-caudal margins of median and cau- 

 dal femora supplied with well spaced hairs. Four proximal tarsal 

 joints scarcely longer than distal joint, supplied with large pul villi. 

 Large arolia present between the simple, symmetrical tarsal claws. 



Zetoborella gemmicula new species. Plate XI U, flgiu*es 1 and 2. 



The shining surface, smooth and very transverse pronotum and 

 emarginate tegmina, which leave the lateral portions of the dorsum 

 of the abdomen exposed, give this beautiful little insect a very dis- 

 tinctive appearance. 



Type: cf; St. Jean du Maroni, French Guiana. April and May. 

 [Paris Museum.] 



In addition to the features discussed above, we note the following. 

 Interocular width three times ocular depth. Fourth joint of maxil- 

 lary palpi half as long as third, fifth joint three-quarters as long as 

 third, greatly expanding, its greatest width equal to length of fourth 

 joint. 1* Pronotum extending well beyond head, with cucullation 

 above head flattened, surface broadly concave before the two latero- 

 caudal emarginations, the first of these very weak and lateral in 

 position, the second decided and caudad in position, twice as long 

 as broad, with angulate-emargination formed sharply rounded at 

 shghtly less than a right angle. Tegmina extending slightly be- 

 yond cereal apices. 



Allotype: 9 ; same data as type. [Paris Museum.] 



Very similar to male, except as follows. Interocular width three 

 and one-half times ocular depth. Maxillary palpi with fifth joint 

 as long as third and wider than length of fourth. Pronotum slightly 

 less strongly transverse, with latero-caudal emarginations less de- 

 cided, so that the caudal emarginations have the angulate-emar- 



" In the specimens of Tribonidium here recorded the limbs are unarmed except 

 the ventro-cephahc margin of the cephahc femora, which is supphed in distal 

 portion with a row of minute, chaetiform spines, terminated by a single stout, 

 though very small, distal spine. The metatarsus is equal in length to the distal 

 tarsal joint. 



'* Apparently somewhat variable, as in the allotype it is even wider. 



