104 



INSECTS OF SAMOA. 



Chiastoplonia, gen. n. 



Allied to Mezira, Am. et Serv., but differs in the following characters : 

 Tylus very short, extending scarcely beyond the insertion of the antennae and 

 not at all beyond the antenniferous teeth. Scutellum with percurrent longi- 

 tudinal and transverse ridges in the form of a cross. Corium very short, scarcely 

 extending beyond the apex of scutellum, the clavus extending distinctly beyond 

 the adjoining region of the corium. Membrane large and smooth without 

 distinct veins. Spiracles of second and third (actual) abdominal segments on 

 lateral edge of connexivum instead of placed ventrally. 



Genotype : — Chiastoplonia pygmaea, sp. no v. 



20. Chiastoplonia pygmaea, sp. n. (Text-fig. 6). 



Colour. — (J. Head, pronotum, and scutellum dark ferruginous brown, 

 antennae, sternum, venter, connexivum, and legs ferruginous brown. Mem- 

 brane greyish, paler towards apex of clavus, shading to black towards the costal 

 margin. 



Structure. — ^Head nmch broader than long (28 : 19), tylus indistinctly delimited 

 from juga, not at all produced anteriorly its apex level with the apices of anten- 

 niferous tubercles which are short and broad and form rectangular teeth with 

 the posterior side parallel to the axis of the head ; postocular spines obtuse 

 but not obsolete ; vertex with broad, distinct, longitudinal ridge ; antennae 

 about as long as head and pronotum together, the first segment strongly 

 incrassate, much thicker than others, about twice as long as wide, nearly equal in 

 width to the length of eye ; second segment less strongly incrassate but much 

 wider at apex than at base ; third segment longest, gradually widening towards 

 apex ; fourth robustly fusiform the widest part nearer the apex, apical fourth 

 covered with long white hairs ; relative lengths of segments 12:10:15:12; 

 rostrum scarcely extending beyond buccal groove, in which it lies, the bucculae 

 moderately well elevated, parallel. Pronotum twice as broad at the base as 

 long (60 : 29) equally broad anteriorly as long ; lateral margins carinate anterior 

 to humeral angles ; those of posterior lobe straight, strongly converging 

 anteriorly ; those of anterior lobe, at first parallel then converging, at same 

 angle as those of posterior lobe, to anterior lateral angles ; anterior margin 

 straight ; posterior margin moderately emarginate above base of scutellum ; 

 humeral angles rounded ; disc of anterior lobe with a pair of large circular 



