TENTHREDIKID.E. LYDA. 97 



Genus XXVIIL— LYDA, Fabricius. . 



AntenncB setaceous, consisting of numerous articulations, stoutest in the males, 

 the basal joint most robust, 2nd minute, 3rd not longer than the 1st, the 

 remainder very gradually decreasing in length and thickness to the end, the 

 terminal joint being minute : clypeus semicircular, nearly concealing the 

 mouth : mandibles strongly bidentate : head very large, somewhat orbicular, 

 or, viewed from above, subquadrate : e^/e.? small, prominent: ocelli 3: thorax 

 broad, slightly convex: win^s large and broad; anterior with 2 marginal 

 areolets, the 3 basal ones being complete, the 1st smallest, nearly trian- 

 gular, the 2nd elongate and curved, the 2rd nearly parallelogrammic, the 

 4th incomplete, not extending to the apex : abdomen generally broad and 

 depressed, terminal joint elongate in the male; ovipositor short: legs 

 slender, shortish ; the 4 posterior tibia; with a single spur in the middle, 

 2 below the middle and 2 at the apex. Larvte gregarious, without prolegs, 

 the apex terminated with 2 horn-like protuberances. 

 The conspicuous and generally beautiful insects included in this 

 fine genus may be readily known from Tarpa, by having the antennas 

 simple, the body broader and more depressed, the wings also broader, 

 and the areolets somewhat dissimilar ; and, in addition, the 4 posterior 

 tibifE have only 1 spur in the middle, a pair below the middle, and 

 another pair at the apex. The species are mostly very rare, although 

 the larvae are gregarious, which must account for some of them 

 being somewhat common in particular localities, as hereafter men- 

 tioned. 



Sp. 1. Sylvatica. Atra, antennis, articuh basali supra, excepto, thoracis maculis, 

 pedibusqiie luteis, femorvm basi coxisque nigris. (Long. corp. 4§ — 5^ hn. ; 

 Exp. Alar. 7i— 9i lin.) 



Te. Sylvatica. Limie.—ljY. Sylvatica. Steph. Catal. 340. No. 3966. 



Antennas luteous, with the basal joint black above ; head black, with a spot 

 behind, and the palpi luteous ; mandibles testaceous ; thorax black, with 

 the wing scales and scutellum luteous; abdomen black; legs luteous, with 

 the base of the femora and the coxae black ; wings hyaline, slightly flaves- 

 cent, with the nervures brownish, and stigma black. 



Male with the antennae longer, and the upper marghi of the clypeus narrowly 

 edged with yellow. 

 Not very uncommon : taken in June and July in hedges on the 



borders of woods within the metropolitan district, and in Devonshire. 



Sp. 2. Stigma. Nigra, antennis luteis, collaris margine, capitis thoracisque 

 maculis pedibusque fiavis, femorum posticorum basi coxisque nigris. (Lon^. 

 corp. 5 lin. ; Exp. Alar. 10 lin.) 



Ly. Stigma. Steph. Catal. 340. No. 3967. 



Mandibulata, Vol. VII., 30th Sept., 1835. g 



