TENTHREDINID.E. HEMICHIIOA. 55 



Genus XVIII.— HEMICHROA* mihi. 



Antennae setaceous, 9-jomted, elongate, 2 basal joints short, remainder slender, 

 3rd and 4th long, of equal length, 5th rather shorter, the rest gradually 

 diminishing in length : c/T//)eM5 deeply notched : Zairam rounded: mandibles 

 bidentate within : maxillary palpi with the 2 basal joints short, 3rd broad 

 and longer, 2 following more elongate, 6 slender and curved ; labial with 

 the 3rd joint dilated: head large, produced between the antennae: eyes 

 small : ocelli 3 : wings rather short, broad, ample, with 2 nearly equal 

 marginal areolets, divided by a straight nervure, and 4 submarginal ones, 

 the 1st small, rounded; 2nd longest, receiving 2 recurrent nervures ; 3rd 

 small, elongate-quadrate ; 4th extending to the apex ; abdomen short, some- 

 what robust : legs short, simple : tibiae with 2 spurs at the apex only. 

 This genus differs not only in general habit— as may be seen by 

 the figures (pi. xxxviii. f. 2.) — from Selandria, but also in the structure 

 and slenderness of its antennse, wings, he. : the latter are particularly 

 prone to vary, especially the marginal areolet, scarcely two examples 

 occurring precisely alike ; in some there is only 1 areolet, others 

 have 2, and some have the rudiments merely of the separating 

 nervure, while in others it extends either half way or nearly to the 

 maro-in : in general the species are of contrasted colours. 



Sp. 1. Alni. Plate xxxviii./. 2.— Nigra, capiie thoraceque rufo-testaceis,pedibus 

 anticis subtestaceis. (Long. corp. 3^—4 lin. ; Exp. Alar. 8— 8| lin.) 



Te. Alni. Linnc.—^e. Alni. Staph. Catal. 332. No. 3861. 



Head testaceous-red ; eyes, ocelli, and antennse black, the basal joints of the 

 last reddish beneath: mandibles brownish or dusky; thorax testaceous- 

 red ; abdomen rich shining-black; legs black, anterior somewhat testaceous; 

 wings hyaline, the nervures brownish, and the costa and stigma yellowish- 

 brown. 

 Not common; taken at Darenth and Birch woods occasionally 



towards the end of June, and at Forest Hill on the 28th of July 



last. 



Sp. 2. rufa. Luteo-rvfa, antennis, sterno, femoribusque posticis nigris, tihiis 

 posticis albidis, apice cum tarsisfuscis. (Long. corp. 3§ — 4 lin.; Exp. Alar. 



8— Silin.) 

 Te. rufa. Panzer.— ^e. rufa. Steph. Catal. 332. No. 3862. 

 Head luteous-red; antennse dusky-black; eyes and ocelli black; thorax 



rufous above, with a dusky or blackish patch behind the scutellum, and 



* E/ncryf dimidius, tcpoa color. 



